Add GitHub Actions CI test

[haata]

Very basic GitHub Actions configuration.

[kentonv]

Thanks for writing this!

I wonder why the action didn't actually run on this PR itself? It would be nice to see that it passes before merging. I was under the impression that PRs were allowed to modify workflows, and those modifications would actually be used when running the workflow on the PR, so I don't get why it's not happening here.

I wonder if node.js is possibly not a valid action name, because it contains a .... I would name it just test.

[haata]

Yeah, I'm not sure how the Actions stuff works for PRs. I think there's some sort of approval process to even enable actions (so you don't just get random PRs running code for actions, but I'm not too sure). The Actions work on my own fork, so I know they run https://github.com/haata/node-capnp/actions.

I still need to do some work on the Windows version of this, haven't been able to get it to compile yet. Will post a separate PR when it's ready.

[ocdtrekkie]

I am thinking it'll only run on a PR where the branch name is node10...

Actions shouldn't need any permission to run, it's just that Actions on PRs can't access secrets, generally.

[ocdtrekkie]

Sandstorm's is just on: [push, pull_request] and I think that probably would work fine here.

[haata]

I made the change, still doesn't seem to show up here.
Again, works on my branch: https://github.com/haata/node-capnp/actions/runs/393176929