CI/CD-only does not work properly when force pushing branches
### Summary
CI/CD-only projects when used do not support force pushing of upstream projects.
### Steps to reproduce
1. Create a new project on GitHub,
1. Commit on GitHub,
1. Create a CI/CD-only project on GitLab,
1. Amend and force push to GitHub,
1. Expect to see the same commit on GitLab.
### What is the current *bug* behavior?
This fails as a newly created project has Protected Branches configured on master which prevents mirroring from updating the target branch.
### What is the expected *correct* behavior?
Protected Branches should not be configured for mirrored / CI/CD-only projects.
issue