Set pyfaust whl rev pkg to py3.11 (previously to py3.10) -- pkg_linux_purepy_rev ci job.

Two reasons:
- pkg_linux job which depends on pkg_linux_purepy_rev is already set to py3.11 (it should avoid rebuilding the py wrappers).
- pyfaust_test_code_coverage job produces a better coverage rate with py3.11 because some tests fail on py3.10 (cf. issue #324).