Give testing/troubleshoot details on PR comment

[chadwcarlson]

Addresses comment component of #61.

[github-actions]

Hello, and thank you for contributing to the Upsun demo project!

Setting up tests

Most tests will run automatically when you open a pull request, while others require contributors with write access to enable.
Until all tests pass, a pull request will not be merged.

enable instructions tbd

Failing tests

If your PR is failing, see the Running tests section of the README for troubleshooting details.

Reviewing these changes locally:

1. Clone this repo

   git clone -b commenton-pr [email protected]:platformsh/demo-project.git demo-test-commenton-pr && cd demo-test-commenton-pr

2. Create a project on Upsun:

   upsun project:create --title "Demo Project test (pr-78/merge)" --default-branch commenton-pr

   This command will set the local repository remote automatically, but you will need to specify the organization and region.

3. Push to Upsun:

   upsun push