Automatically push Docker image to Amazon ECR

[ErikSchierboom]

The v3 website uses Docker images from Amazon ECR for all the tooling.
Each tooling repo should have a workflow to automatically push to Amazon ECR whenever something is merged to master.

This PR adds a GitHub Actions workflow to automatically build and push a new Docker image whenever something is merged to master.

See exercism/v3#2728

[cmccandless]

I'm not sure this template repository should be pushing to ECR, but I do agree that this workflow should be included here somehow... Perhaps we can include it and disable it somehow, then add to the instructions for using this repo how to enable it?

[ErikSchierboom]

Agreed. @SaschaMann what would be the best way to disable a workflow?

[SaschaMann]

Ask @iHiD to disable actions for this repo: https://github.com/exercism/generic-test-runner/settings/actions

[cmccandless]

I'm ok with that. The unit test workflow for pull_request doesn't actually run anything important.

[cmccandless]

Do we also need to add instructions to https://github.com/exercism/generic-test-runner/blob/master/README.md to ping an admin to add AWS credentials to any new test-runner created from this template?

[ErikSchierboom]

That's a good idea.

[cmccandless]

@iHiD As mentioned above (#21 (comment)), we need Github Actions disabled for this repository. Has that been done?

[iHiD]

Yes it has.

[cmccandless]

Thanks @ErikSchierboom @iHiD @SaschaMann

[iHiD]

And thank you!