Resolves #1537

Behavior

Before the change?

The following code errors if both GITHUB_APP_... and GITHUB_TOKEN env vars are set:

provider "github" { # Uses GITHUB_APP_... env vars
  app_auth {}
}

The error message looks like this:

│ Error: no decodeable PEM data found
│ 
│   with provider["registry.terraform.io/hashicorp/github"],
│   on main.tf line 1, in provider "github":
│    1: provider "github" {

After the change?

• app_auth {} block set => Provider uses the GITHUB_APP_... env vars (currently the case*), ignores GITHUB_TOKEN env var (new)
• app_auth {} block not set => Provider uses the GITHUB_TOKEN env var (currently the case*), ignores GITHUB_APP_... env vars (currently the case*)

Other information

Additional info

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Added the appropriate label for the given change

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes (Please add the Type: Breaking change label)
• No

If Yes, what's the impact:

• N/A

Pull request type

Please add the corresponding label for change this PR introduces:

• Bugfix: Type: Bug
• Feature/model/API additions: Type: Feature
• Updates to docs or samples: Type: Documentation
• Dependencies/code cleanup: Type: Maintenance