deps: Upgrade react-native-webview to ~10.0.0.

We'd like to upgrade to the latest, but versions 10.1.0 and above
don't have support for RN v0.61; minimum supported is v0.62. (Hence
the tilde.)

We hesitate to take an x.0.0 version -- what if there are important
bugfixes in minor/patch versions for issues introduced in that x.0.0
version? -- but they've made it a custom to post a note at the
release if they know of major regressions, telling you to use a
later version [1]. And no such note exists at v10.0.0.

As a concrete example, we were concerned that the "bug fixes"
identified in the v10.1.0 release might have been aimed at
regressions introduced in v10.0.0. But following links to the
mentioned PR and its corresponding issues (the second looks like a
resumption of the first), it looks like a fix for a bug reported all
the way back in version 5. So this isn't a reason to use v9.x.x
instead of v10.0.0.

Greg points out [2]:

"""
In a project that takes major vs. minor releases seriously, where a
minor release means cherry-picked backported changes, I'd assume
from this context that the major release introduced the issue.

(Projects like that include RN itself, and the Zulip server.)

But with this project I get the impression that their releases are
all a linear stream of snapshots from master. Also that they do the
flavor of "semantic versioning" that's basically "bump the major
version number frequently and at random". So that makes this less
clear.
"""

Ah, well.

[1]: See, e.g., v10.1.0, at
     https://github.com/react-native-community/react-native-webview/releases/tag/v10.1.0.
[2]: https://chat.zulip.org/#narrow/stream/243-mobile-team/topic/RN.20v0.2E61.3A.20react-native-webview/near/901944

ios/Podfile.lock

@@ -222,7 +222,7 @@ PODS:
   - react-native-simple-toast (1.0.0):
     - React
     - Toast (~> 4.0.0)
-  - react-native-webview (8.0.4):
+  - react-native-webview (10.0.0):
     - React
   - React-RCTActionSheet (0.61.5):
     - React-Core/RCTActionSheetHeaders (= 0.61.5)
@@ -536,7 +536,7 @@ SPEC CHECKSUMS:
   react-native-safari-view: 955d7160d159241b8e9395d12d10ea0ef863dcdd
   react-native-safe-area: 5fce5242419932bc05656f31bc5f0716e30be0f6
   react-native-simple-toast: 6c376bd79b1e255a4bee90a72ead6447f96ea10d
-  react-native-webview: 3f5aa91c3cb083ea4762e006b9653291a96a777a
+  react-native-webview: 83d00afd3f3ebfbee7f02d149ce1bfa8494d55f3
   React-RCTActionSheet: 600b4d10e3aea0913b5a92256d2719c0cdd26d76
   React-RCTAnimation: 791a87558389c80908ed06cc5dfc5e7920dfa360
   React-RCTBlob: d89293cc0236d9cb0933d85e430b0bbe81ad1d72

package.json

@@ -71,7 +71,7 @@
     "react-native-unimodules": "0.6.0",
     "react-native-url-polyfill": "1.2.0-rc.0",
     "react-native-vector-icons": "^6.6.0",
-    "react-native-webview": "8.0.4",
+    "react-native-webview": "~10.0.0",
     "react-navigation": "^2.18.3",
     "react-navigation-redux-helpers": "^2.0.9",
     "react-navigation-tabs": "0.8.4",

yarn.lock

@@ -8075,10 +8075,10 @@ react-native-vector-icons@^6.6.0:
     prop-types "^15.6.2"
     yargs "^13.2.2"
 
-react-native-webview@8.0.4:
-  version "8.0.4"
-  resolved "https://registry.yarnpkg.com/react-native-webview/-/react-native-webview-8.0.4.tgz#4951df32bd54f6fa16bc0eda5e6e6762d8b83ba8"
-  integrity sha512-XEatna1wwF43Rg500HaDIC/MS2IAob/PvjkTePCevs9wQz90SwERTjGZNuM2WxH+JwrZrxoilGBOn34vQTTJkw==
+react-native-webview@~10.0.0:
+  version "10.0.0"
+  resolved "https://registry.yarnpkg.com/react-native-webview/-/react-native-webview-10.0.0.tgz#a01c69fbf63d0b12cb8238c09b7baa61e657daa4"
+  integrity sha512-GCROVTfnQr4h/FYEHXYGdlXAifJ7cUjdtpPZgpZNZN4yP8J+VdyZTqJLfgCPsMnZsL+tCr4JAuaoK8GnFjnqLQ==
   dependencies:
     escape-string-regexp "2.0.0"
     invariant "2.2.4"