Compatibility with React 16.13

[xoob]

This maintenance change introduces compatibility with the current stable releases of React, React DOM, and a number of other smaller libraries. We upgrade the libraries and provide bugfixes for several warnings and library behavior changes that were found during testing.

• Fixes Get rid of react warning : componentWillMount has been renamed, and is not recommended for use. salesforce/design-system-react#2386, Get rid of react warning : componentWillReceiveProps has been renamed, and is not recommended for use. salesforce/design-system-react#2385, Getting this test failed when I run npm test  salesforce/design-system-react#2463
• Might fix Prevent javascript URLs warning in React 16.9 salesforce/design-system-react#2384
• Might fix JavaScript URLs in Tab component don't play nicely with strict CSP salesforce/design-system-react#2493

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After the initial upgrade the observed test failures were as follows:

SLDSAlert: [javascript URLs]
    Dismiss alert
        "before each" hook: mountComponentInside for "calls onRequestClose handler"

    Error: Warning: A future version of React will block javascript: URLs as
    a security precaution. Use event handlers instead if you can. If you need
    to generate unsafe HTML try using dangerouslySetInnerHTML instead.

SLDS APP LAUNCHER TILE: [componentWillUpdate]
    App Launcher Tile (truncated)
        "before each" hook for "renders more link"

    Error: Warning: componentWillUpdate has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

     * Move data fetching code or side effects to componentDidUpdate.
     * Rename componentWillUpdate to UNSAFE_componentWillUpdate to suppress this
       warning in non-strict mode. In React 17.x, only the UNSAFE_ name will
       work. To rename all deprecated lifecycles to their new names, you can
       run `npx react-codemod rename-unsafe-lifecycles` in your project
       source folder.

SLDSColorPicker: [componentWillMount]
    Swatch toggle button
        opens popover when clicked and expects onRequestOpen and onOpen to be fired once

    Error: Warning: componentWillMount has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

    * Move code with side effects to componentDidMount, and set initial state in the constructor.
    * Rename componentWillMount to UNSAFE_componentWillMount to suppress this
      warning in non-strict mode. In React 17.x, only the UNSAFE_ name will
      work. To rename all deprecated lifecycles to their new names, you can
      run `npx react-codemod rename-unsafe-lifecycles` in your project source
      folder.

SLDSCombobox: [componentWillUpdate]
    Assistive technology and keyboard interactions
        has aria-haspopup, aria-expanded is false when closed, aria-expanded is true when open‣

    Error: Warning: componentWillUpdate has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

SLDSMenuPicklist: [componentWillMount]
    in modal mode
        "before each" hook for "expands/contracts the dropdown on click"‣

    Error: Warning: componentWillMount has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

SLDSTimepicker: [React.createFactory()]
    Timepicker Value Prop Change
        displays a modified state upon changing props‣

    Error: Warning: React.createFactory() is deprecated and will be removed
    in a future major release. Consider using JSX or use
    React.createElement() directly instead.

Tree: [onScroll timeout?]
    Scrolling calls onScroll
        scrolling calls onScroll‣

    Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure
    "done()" is called; if returning a Promise, ensure it resolves.

SLDS Visual Picker: [componentWillMount]
    radio switching works correctly‣

    Error: Warning: componentWillMount has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

SLDSWelcomeMat: [componentWillMount]
    Steps Variant
        "before each" hook for "renders welcome mat"‣

    Error: Warning: componentWillMount has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

    Trailhead Variant
        "before each" hook for "renders welcome mat"‣

    Error: Warning: componentWillMount has been renamed, and is not
    recommended for use. See https://fb.me/react-unsafe-component-lifecycles
    for details.

---

React DOM: Upgrade from 16.8.6 to 16.13

At the time of this pull request, the master branch of design-system-react
is locked in package-lock.json to react-dom@16.8.6 and react@16.9.0. Unit
tests are succeeding in master.

React DOM version 16.9 introduces two deprecation warnings that cause the
design-system-react test suite to fail after the react-dom dependency is
upgraded:

React DOM

• Deprecate old names for the UNSAFE_* lifecycle methods. (Enabled warnAboutDeprecatedLifecycles flag by default facebook/react#15186 and unify deprecated/unsafe lifecycle warnings, pass tests facebook/react#16103)
• Deprecate javascript: URLs as a common attack surface. (Warn for javascript: URLs in DOM sinks facebook/react#15047)

React: Upgrade from 16.9.0 to 16.13

To keep up-to-date with new React releases, this pull request bumps to the
latest stable version. Notable changes between the old and new version are:

React

• Deprecate React.createFactory() (Add React.createFactory() deprecation warning facebook/react#17878)

Other Upgrades

We use this opportunity to upgrade a few other dependencies that include
small bug fixes and other seemingly useful improvements.

prop-types: Upgrade from 15.6.0 to 15.7.2

https://github.com/facebook/prop-types/blob/master/CHANGELOG.md

react-contenteditable: Upgrade from 3.3.1 to 3.3.4

• Trivial fixes

lovasoa/react-contenteditable@3.3.1...v3.3.4

shortid: Upgrade from 2.2.14 to 2.2.15

• Generate smaller IDs

dylang/shortid@2.2.14...2.2.15

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CONTRIBUTOR checklist (do not remove)

Please complete for every pull request

• First-time contributors should sign the Contributor License Agreement. It's a fancy way of saying that you are giving away your contribution to this project. If you haven't before, wait a few minutes and a bot will comment on this pull request with instructions.
• npm run lint:fix has been run and linting passes.
• Mocha, Jest (Storyshots), and components/component-docs.json CI tests pass (npm test).
• Tests have been added for new props to prevent regressions in the future. See readme.
• Review the appropriate Storybook stories. Open http://localhost:9001/.
• Review tests are passing in the browser. Open http://localhost:8001/.
• Review markup conforms to SLDS by looking at DOM snapshot strings.

REVIEWER checklist (do not remove)

• TravisCI tests pass. This includes linting, Mocha, Jest, Storyshots, and components/component-docs.json tests.
• Tests have been added for new props to prevent regressions in the future. See readme.
• Review the appropriate Storybook stories. Open http://localhost:9001/.
• The Accessibility panel of each Storybook story has 0 violations (aXe). Open http://localhost:9001/.
• Review tests are passing in the browser. Open http://localhost:8001/.
• Review markup conforms to SLDS by looking at DOM snapshot strings.

Required only if there are markup / UX changes

• Add year-first date and commit SHA to last-slds-markup-review in package.json and push.
• Request a review of the deployed Heroku app by the Salesforce UX Accessibility Team.
• Add year-first review date, and commit SHA, last-accessibility-review, to package.json and push.
• While the contributor's branch is checked out, run npm run local-update within locally cloned site repo to confirm the site will function correctly at the next release.