Add branch protection and mypy check

[eirikurj]

Purpose

Per title. See #19 and #21 for details.

Expected time until merged

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run ruff check and ruff format to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[DavidAnderegg]

Hi @eirikurj

Can you remind me why we need client- branches? I think we concluded in one of the dev meetings this would lead to 'code duplication' but on the github level.

Answer (in teams):
I think we still want to use them sparingly. I think last time Andew wanted to have client branches as staging branches for the images since there may be multiple features. We can discuss again.

-> Will approve for the sake of progress but should discuss it further.

[DavidAnderegg]

looks good to me.