Collect improvements and restore tests

[tiennou]

Sorry, I opened that too quickly. I was about to test GH on my repo and ended up opening it there instead.

So, it's the collected changes from the MRs either here or on Arcath's repository. Here's the changelog for it:

• Set up GitHub actions to build and test on pushes and pull requests
• Update all dependencies
• Merge Update just screeps-api #3 and Update all deps and get prepublishOnly working #4, then do some fixups on top
• Switch Mocha for testing for Jest, mostly because I couldn't get it to work
• Fix the way we edit sourcemaps so that 1) the extension is properly added and 2) the file looks like a module to the Node 10 loader
• Remove our typings file for screeps-api and use its own types directly
• Add support for the unified YAML credential file

And the CI build is green on my fork, so

[tiennou]

Do note that I haven't actually ran it. It's just me wanting to add the unified file support, then it turned into a deep dive into why the testsuite is broken, then why is it red, then…

[ShuP1]

Once done, I would be happy to deprecate https://github.com/ShuP1/rollup-plugin-screeps-ss3 repo and npm package for this one

[tiennou]

That would be great @ShuP1. The only snag I hit is that installing this one instead of the Arcath one (which I'm on) causes my build to fail and I'm not sure why. It's complaining about accesses to global, wanting me to use globalThis instead.