Update NPM packages + add 429 http code

[konradpabjan]

• Add the 429 HTTP Code (copied over from the forked Microsoft Typed Rest Client). Will be needed because RU2 might return a 429 if there are too many calls being made and we get throttled.
• Update NPM packages. Should get rid of the security warnings with the acorn package being out of date (see the dependabot PR Bump acorn from 5.7.3 to 5.7.4 #13) along with (most) of the problems that are showing up when running npm audit

[konradpabjan]

Runs are still failing during npm audit, before my changes there were 37k vulnerabilities, now there is 1 (minimist), can't really go away because certain packages that have it as a dependency need to be updated upstream.

I used ncu to update all the packages: https://stackoverflow.com/questions/16073603/how-do-i-update-each-dependency-in-package-json-to-the-latest-version

[ericsciple]

@bryanmacfarlane fyi since he will need to release

seems good to me

[bryanmacfarlane]

LGTM