Convert to a JavaScript action

[JasonEtco]

I'd like to convert this to being a JavaScript action, so that users of it don't need to build the Docker container in their workflow - it'd be a little faster ⚡️

However, committing node_modules is a non-starter for me - I think that's an anti-pattern that I'm absolutely going to avoid. Tools like @zeit/ncc are a good enough compromise, so I'll be trying that out (also would mean I can write TypeScript actions without any extra work 😍).

I'd like to investigate/setup a GitHub Actions workflow to do the building and publishing to the specific tags, to avoid having a dist folder in the master branch (again, an anti-pattern). @mheap 👋 has done some awesome work on github-action-auto-compile-node, I'm hoping to just pull that in, potentially also with Actions Tagger.

cc this Twitter thread