Track code coverage

[JeanChristopheMorinPerso]

OpenSSF Best Practices badges requires us to have code coverage and track coverage over time.

It's a good thing to have anyway :)

Requirements:

• https://www.bestpractices.dev/en/projects/8389?criteria_level=1#test_statement_coverage80
• https://www.bestpractices.dev/en/projects/8389?criteria_level=2#test_branch_coverage80