make CI run faster on development branches

Don't need all the jobs for work-in-progress branches.
0 jobs for !3 with split-classic-ci-2
latest yaml invalid error detached

Found errors in your .gitlab-ci.yml:

  • validate: needs '1.9.0-coq-8.10' proof-state: needs '1.9.0-coq-8.10'
You can also test your .gitlab-ci.yml in CI Lint