If there is no release-drafter configuration file in a repository, the file in
the .github repository will be used.

In addition, introduce a new GitHub workflow to ensure that the PR titles match
conventional commits.

Notes

See the documentation of the release-drafter shared configuration:

Release Drafter also supports [Probot Config](https://github.com/probot/probot-config),
if you want to store your configuration files in a central repository.
This allows you to share configurations between projects, and create a
organization-wide configuration file by creating a repository named .github with the file .github/release-drafter.yml.