* Add workflow to remind PR reviewers to also review the testing instructions.
* Update review-testing-instructions GitHub Actions workflow to also mentioning teams in the comment.
* Update review-testing-instructions GitHub Actions workflow to find if the comment it posts was already posted and - in that case - update it instead of creating a new one.
* Pin find-comment and create-or-update-comment thirdparty GitHub Actions to full length commit SHA instead of tag for better security.