bump Iris, fix build

1 job for master in 5 minutes and 27 seconds (queued for 4 minutes and 21 seconds)
Status Job ID Name Coverage
  Build
failed #22444
fp-timing
build-coq.8.8.2

00:05:27

 
Name Stage Failure
failed
build-coq.8.8.2 Build
Makefile.coq:317: recipe for target 'all' failed
make[1]: *** [all] Error 2
Makefile:6: recipe for target 'all' failed
make: *** [all] Error 2

real 4m19.578s
user 17m20.120s
sys 0m30.428s
ERROR: Job failed: exit code 1