readme: fix linter badge

[Borda]

Description

It seems that the workflow was renamed, so the badge is wrong:

• actual ->
• fixed ->

Checklist

• Linked issues (if existing)
• Amended changelog for large changes (and added myself there as contributor)
• Added/modified tests
• Used pre-commit hooks when committing to ensure that code is compliant with hooks. Install hooks with pre-commit install.
  To run hooks independent of commit, execute pre-commit run --all-files

Make sure to have fun coding!

cc: @jdb78