checkstyle-tester: unused project.properties files #880
Description
detected at #878 (comment)
We have files that are not used by any of our jobs or diff reports, examples :
- https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/github-action-projects1.properties
- https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/github-action-projects2.properties
- https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/latest-projects-to-test-on.properties
Having a lot of project files that are not used may be confusing. We should remove them, otherwise, we will document why we need the files.