Request Flocq update to 4.2.2: build fails because of Zmod -> Z.modulo change in rocq 9.1.0

Hi, when building from `master` on Rocq 9.1.1, I get this error:
```
File "./flocq/Core/Zaux.v", line 327, characters 2-6:
Error: The reference Zmod was not found in the current environment.
```
I looked around and updating `flocq` to `4.2.2` seems to be the fix.
(a simple `find flocq -type f -name "*.v" -exec sed -i 's/\bZmod\b/Z.modulo/g' {} +` works)

Thanks.