Move CI to use Ansible 2.12 version as main

Move only from victoria, since Ansible 2.12 is installed with
py > 3.8.
Remove ussuri from voting jobs, use it for experimental only.
Change-Id: I74b7272794ea5fbafb7d81a5cf0068c09130bb0d

tox.ini

@@ -65,6 +65,12 @@ commands = {[testenv:linters]commands}
 deps =
     -r{toxinidir}/test-requirements-2.11.txt
 
+[testenv:linters-2.12]
+passenv = {[testenv:linters]passenv}
+commands = {[testenv:linters]commands}
+deps =
+    -r{toxinidir}/test-requirements-2.12.txt
+
 [testenv:venv]
 deps =
     -r{toxinidir}/test-requirements.txt
@@ -112,6 +118,12 @@ deps =
 passenv = {[testenv:ansible]passenv}
 commands = {[testenv:ansible]commands}
 
+[testenv:ansible-2.12]
+deps =
+    -r{toxinidir}/test-requirements-2.12.txt
+passenv = {[testenv:ansible]passenv}
+commands = {[testenv:ansible]commands}
+
 [testenv:galaxy-release]
 deps =
     ansible-core