.github/workflows/ci.yml: re-enable Ubuntu 20.04 in the CI workflow
.github/workflows/ci.yml: re-enable Ubuntu 20.04 in the CI workflow

We need to figure out how to make this work and pass.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp