update CONTRIBUTING

5 jobs for master
Status Name Job ID Coverage
  Build
canceled build-coq.8.6.1 #6790
fp-timing

canceled build-coq.8.7.0 #6789
fp-timing

 
  Deploy
canceled opam #6791

canceled reverse-deps #6792

 
  Build More
canceled build-coq.8.7.dev #6793
fp-timing