update the Coq versions we test against

1 job for master in 16 minutes and 13 seconds (queued for 4 seconds)
Name Stage Failure
build-iris.dev Build
make[1]: *** [all] Error 2
make[1]: Target 'ci' not remade because of errors.
Makefile:6: recipe for target 'ci' failed
make: *** [ci] Error 2

real 0m12.826s
user 1m14.420s
sys 0m5.540s
ERROR: Job failed: exit code 1