Stop supporting zope.app.wsgi < 3.11

This breaks with setuptools >= 8.0, since multiple constraints are
logically ANDed now, as per PEP 440, and this results in an inherent
contradiction.

The contraint was originally introduced in
8f8c3bbf3f96271673f8566875cc8965d23202f5 with no explanation of why 3.11
was a bad zope.app.wsgi version to use.