Drop py38 based jobs and add py310 instead

2023.2 Bobcat's runtimes [1] are py39 and py310, so this patch removes
py38 based jobs and adds py310 ones instead.

[1] https://governance.openstack.org/tc/reference/runtimes/2023.2.html

Change-Id: I9c335ef2685e48e713beed148924a737bd2c1087

.zuul.yaml

@@ -15,8 +15,8 @@
       - release-notes-jobs-python3
     check:
       jobs:
-        - openstack-tox-functional-py38
         - openstack-tox-functional-py39
+        - openstack-tox-functional-py310
         - openstack-tox-pep8
         - placement-nova-tox-functional-py39
         - placement-nested-perfload:
@@ -46,8 +46,8 @@
             irrelevant-files: *gate-irrelevant-files
     gate:
       jobs:
-        - openstack-tox-functional-py38
         - openstack-tox-functional-py39
+        - openstack-tox-functional-py310
         - openstack-tox-pep8
         - placement-nova-tox-functional-py39
         - tempest-integrated-placement:
@@ -78,6 +78,17 @@
         # to skip the api|notification _sample_tests and db-related tests.
         tox_envlist: functional-without-sample-db-tests
 
+- job:
+    name: placement-nova-tox-functional-py310
+    parent: nova-tox-functional-py310
+    description: |
+        Run the nova functional tests to confirm that we aren't breaking
+        the PlacementFixture.
+    vars:
+        # 'functional-without-sample-db-tests' tox env is defined in nova tox.ini
+        # to skip the api|notification _sample_tests and db-related tests.
+        tox_envlist: functional-without-sample-db-tests
+
 - job:
     name: placement-perfload
     parent: base