Enable Branch protection rules for main branch on this repo

[tfr42]

https://github.com/deegree/deegree3/settings/branch_protection_rules/

[tfr42]

Documentation: https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/managing-a-branch-protection-rule
Outcome of the discussion during TMC meeting 2022-07-27:

• enable for main branches such as main and main-3.4
• exceptions for CI seem to be possible with "Allow specified actors to bypass required pull requests"

[tfr42]

Protection rule created for main with:

• Require a pull request before merging
• Allow specified actors to bypass required pull requests Specify people, teams, or apps who are allowed to bypass required pull requests. For user "deegree-ci".
• Include administrators