Remove python 3.9 test jobs

Python 3.9 is not supported anymore in the Openstack ecosystem
We should just remove tests that use it.

Change-Id: I11f87d00f9c36247cd252acfc5bfd3cc7bfb143c
Signed-off-by: Riccardo Pittau <elfosardo@gmail.com>

.zuul.d/project.yaml

@@ -17,7 +17,6 @@
         - requirements-tox-babel
         - requirements-tox-bindep:
             voting: false
-        - requirements-tox-py39-check-uc
         - requirements-tox-py310-check-uc
         - requirements-tox-py311-check-uc
         - requirements-tox-py312-check-uc
@@ -82,7 +81,6 @@
         - openstack-tox-validate
         - requirements-check-self
         - requirements-tox-babel
-        - requirements-tox-py39-check-uc
         - requirements-tox-py310-check-uc
         - requirements-tox-py311-check-uc
         - requirements-tox-py312-check-uc
@@ -119,7 +117,6 @@
       jobs:
         - nova-ceph-multistore
         - nova-next
-        - requirements-tox-py39-check-uc-no-wheels
         - requirements-tox-py310-check-uc-no-wheels
         - requirements-tox-py311-check-uc-no-wheels
         - requirements-tox-py312-check-uc-no-wheels

tox.ini

@@ -12,13 +12,6 @@ deps = -c{toxinidir}/upper-constraints.txt
 commands =
   stestr run {posargs}
 
-[testenv:py39-check-uc]
-allowlist_externals =
-  check-conflicts
-basepython = python3.9
-deps = -r{toxinidir}/upper-constraints.txt
-commands = check-conflicts {toxinidir}/upper-constraints.txt {toxinidir}/upper-constraints-xfails.txt
-
 [testenv:py310-check-uc]
 basepython = python3.10
 deps = -r{toxinidir}/upper-constraints.txt