Update dependencies and test targets

[westy92]

• Update TypeScript and other dependencies.
• Update test targets. Current LTS and stable are 14.x and 15.x (https://nodejs.org/en/about/releases/).
• Cleanup code; update imports to improve type hints and remove deprecations.

[Niek]

@patrickhulce any chance to merge this?

[patrickhulce]

thanks @westy92 all of your stated goals are great 👍

just don't think we want to introduce breaking changes parts of this right now. maybe file an issue for the collection of breaking changes we'll want to batch for the next major? :)

[westy92]

I reverted the changes that require Node.js 10+. I'm happy to open another PR once this lands that drops Node.js 8.x support that can sit around until the project is ready for it.

[patrickhulce]

thanks for working on this @westy92 !

[westy92]

You're welcome! I addressed all the comments and it looks like all the tests passed. 🎉 Is there anything else I need to do to get this merged in?

[patrickhulce]

nope I was just waiting on the tests and then forgot about it :) thanks @westy92 !

[westy92]

I'm happy to open another PR once this lands that drops Node.js 8.x support that can sit around until the project is ready for it.

Just to close the loop on this, here's my promised PR: #222