Implement bindings to the @actions/github package

[colinwahl]

Right now this library does not expose bindings to the @actions/github package. In order to support the full actions toolkit, we will need bindings to that package.

[colinwahl]

I took a look at the @actions/github package and it seems like this one will be the most complicated to implement (with the oktokit stuff). If someone is interested in trying to write bindings.

However, it looks like we could write bindings around context pretty easily, which would be a great first step to getting this done.