Add python 3.10 image and testing

.gitlab-ci.yml

@@ -145,7 +145,7 @@ python-3.9:
       - htmlcov/
     expire_in: 30 days
 
-python-3.10:
+.python-3.10:
   <<: *unit-test
   needs: ["basic-3.10", "precommits-py3.10"]
   image: containers.ligo.org/lscsoft/bilby/v2-bilby-python310
@@ -169,7 +169,7 @@ python-3.9-samplers:
   needs: ["basic-3.9", "precommits-py3.9"]
   image: containers.ligo.org/lscsoft/bilby/v2-bilby-python39
 
-python-3.10-samplers:
+.python-3.10-samplers:
   <<: *test-sampler
   needs: ["basic-3.10", "precommits-py3.10"]
   image: containers.ligo.org/lscsoft/bilby/v2-bilby-python310