Track code coverage for contribs

[paulheinr]

The code coverage of MATSim is tracked here: https://app.codecov.io/gh/matsim-org/matsim-libs
I think it might also be usefull to track the coverage in the contribs. @michalmac Do you know how that works?

[michalmac]

I was never a big believer in the code coverage stats, therefore I only enabled it for the main matsim (as it was also the case before, i.e. when calculating the coverage on our private Jenkins CI).

I guess you need to change https://github.com/matsim-org/matsim-libs/blob/master/.github/workflows/code-coverage.yaml so that the Create coverage report step is run for the whole matsim.

[michalmac]

There is even some little discussion here: #2059