add commit message validator

[eheimbuch]

Proposed changes

Add commit message issue key validator

Your checklist for this pull request

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [x] PR is well described
• [x] Related issues linked to PR if existing and labels set
• [x] Target branch is not master (in most cases develop should bet the target of choice)
• [x] Code does not conflict with target branch
• [x] New code is covered with unit tests
• [ ] CHANGELOG.md updated
• [ ] Definition of Done's fulfilled: DoD // UI DoD
• [ ] Documentation updated (only necessary for new features or changed behaviour)

Checklist for branch merge request (not required for forks)

• [ ] Branch is green/blue on Jenkins
• [ ] Quality Gate passed on SonarQube

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
1 Code Smell

90.0% Coverage
0.0% Duplication