Uncap zuul_pip_version

All of our fixes have now landed.

Depends-On: https://review.opendev.org/c/windmill/windmill-config/+/797656/
Depends-On: https://review.opendev.org/c/windmill/windmill-config/+/797663
Change-Id: I7c83244fd32adb5ae25dd0e1feea2da4aa8b0a92
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

tests/extra-vars/pip.yaml

@@ -4,8 +4,3 @@
 zuul_user_name: zuul-test
 zuul_user_group: zuul-test
 zuul_user_home: /var/lib/zuul
-
-# NOTE(pabelanger): Pin zuul until we have zookeeper SSL working
-zuul_pip_version: 3.19.1
-# NOTE(pabelanger): Needed to install database dependencies
-zuul_pip_name: zuul[mysql_reporter]