get outputs for use in github actions

Hi! Thank you very much for creating these actions. They've made it a lot easier for me to build out the continuous deployment workflow I want.

One feature request that I have is the ability to get the Terraform outputs to be used in my Github Actions. For instance, after Terraform Apply Run I want to be able to push my Docker image to the AWS ECR repo that I created with Terraform. This requires me to have the repository URL and the AWS IAM role that Github should assume to be able to get the repository login credentials.

For now I've created [a get-terraform-outputs action](https://github.com/marketplace/actions/get-terraform-outputs) to handle this for me, but it would be really nice if this was included in the official workflows.

Or if there's some reason why I shouldn't do this, I would love to know that as well.

Thanks!