update CI for opam 2

2 jobs for master in 23 minutes and 48 seconds (queued for 10 minutes and 54 seconds)
Status Job ID Name Coverage
  Build
failed #17856
fp
build-coq.8.6.1

00:17:21

passed #17855
fp
build-coq.8.7.2

00:17:00

 
Name Stage Failure
failed
build-coq.8.6.1 Build
COQC theories/examples/symbol.v
make[1]: Target 'all' not remade because of errors.
Makefile:6: recipe for target 'all' failed
make: *** [all] Error 2

real 5m19.480s
user 13m3.796s
sys 0m20.288s
ERROR: Job failed: exit code 1