Update mimemagic

[differentreality]

• Update mimemagic due to licensing issues
• gh actions failed to work with ruby v 2.5.8 (not sure if we want to update ruby version for actions or we need to look into this from another angle)

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the upstream master branch.
• The tests pass locally with my changes.
• I have added tests that prove my fix is effective or that my feature works(if appropriate).
• I have added necessary documentation (if appropriate).

Short description of what this resolves/which issues does this fix?:

Changes proposed in this pull request:

[hennevogel]

gh actions failed to work with ruby v 2.5.8

How did it fail?

[differentreality]

https://github.com/openSUSE/osem/pull/2746/checks?check_run_id=2316875818

Your Ruby version is 2.5.9, but your Gemfile specified 2.5.8