Coverage badge should be generated in CI, not in pre-commit

[Astariul]

We can't update file in a precommit hook. Things like code coverage should be updated in a CI check, not in a pre-commit, because it would be very annoying while developing to have something to commit (code coverage report) every commit. Instead, just run it when we are pushing !

coverage-badge -f -o .github/badges/coverage.svg

Should be run only in github actions.