Add Github Actions BuildAgent

[arturcic]

[VikingTristan]

Hey, I have a question. I'm having some trouble wrapping GitVersion environment variables together with github action workflows. Is this related?

[arturcic]

This issue is for adding GitHub Action support as build agent, basically when running inside of a GithubAction agent it will have the context of the agent available and it will consume the env variables, and/ or set the env vars

[arturcic]

https://github.com/GitTools/GitVersion/tree/master/src/GitVersionCore/BuildServers as examples

[StanleyGoldman]

I'm starting this pull request now.

[StanleyGoldman]

The PR is good to go!

[StanleyGoldman]

@VikingTristan if you want to give my pull request a try, I could use the validation that it works.

[VikingTristan]

Sure! Is it possible for me to tell my agent to download your specific gitversion pull request build?

With something like choco install gitversion.portable x.x.x-xx