add workflow to build and deploy typescript declarations

[cgsdev0]

I moved my type generation code out of my personal project and into a github action so that it can be easily automated here. You can see a sample of the generated typescript declarations:

https://cdn.jsdelivr.net/npm/[email protected]/index.d.ts

Testing

1. I tested this action in a separate repo
2. I deployed the package to npm
3. I ported my project to use the live npm package

TODO

• add a README.md to npm-types/ (shows up on the npm page)
• set up a NPM_TOKEN secret on this repo
• add whoever's token that is to the maintainer list on npm
• somehow we need to bump the version in package.json or npm will reject subsequent deploys