Updated packages with security vulnerabilities.

[bhtandev]

What did you implement

Updated third party packages with security vulnerabilities. mkdirp and update-notifier.

These were detected by SYNK. Images shown below:

How can we verify it

Run existing tests

• Write and run all tests
• Write documentation
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: NO
Is it a breaking change?: NO

[bhtandev]

Currently stuck as unit tests on for Nodejs 6 is failing because it is not happy with the new update-notifier package. (unexpected identifier - async )

[medikoo]

@bhtandev great thanks for that PR. Still we cannot drop support for Node.js v6 now (it'll be a breaking change, that requires major bump).

Track #7486 for status on that