ci: move tests/integration/test_crossmodel.py to integration-quarantine

Author: james-garner-canonical

tox.ini

@@ -67,6 +67,7 @@ commands =
         --tb native \
         -ra -v -n 1 \
         -k 'integration' \
+        --ignore {toxinidir}/tests/integration/test_crossmodel.py \
         --ignore {toxinidir}/tests/integration/test_model.py \
         -m 'not serial' \
         {posargs}
@@ -81,6 +82,7 @@ commands =
         -ra -v -n 1 \
         -m 'not serial' \
         {posargs} \
+        {toxinidir}/tests/integration/test_crossmodel.py \
         {toxinidir}/tests/integration/test_model.py
 
 [testenv:unit]