#1: validate required workflows usage across repositories

[tlamonthezie]

Create a workflow verifying (automatically using a CRON) that all other repositories in the Github DARMA organization correctly call the required workflows

• action-git-diff-check.yml
• check-commit-format.yml
• check-pr-fixes-issue.yml
• find-trailing-whitespace.yml
• find-unsigned-commits.yml

The idea is to check that each repository contains these yaml files under the .github/workflows directory. And if not then generate an error message to say which repository is not compliant and for which file.

Some workflows might have custom arguments (e.g. find-trailing-whitespace excluded files) so in those cases we might to test the file name and that the use: [workflow] is called. In other strict cases we have to check that files are exactly as initial files (we can compare with files in this repository).