Temporarily remove 3.6 testing

The current 3.6 docker build appears to be broken. This merge request temporarily removes the 3.6 test pipeline before the upcoming release. https://hub.docker.com/repository/docker/bilbydev/v2-dockerfile-test-suite-python36/general

This also means other MRs can be merged if they only fail the 3.6 test pipeline

.gitlab-ci.yml

@@ -71,13 +71,13 @@ python-3.7:
       - docs/_build/html/
 
 # test example on python 3.6
-python-3.6:
-  stage: test
-  image: bilbydev/v2-dockerfile-test-suite-python36
-  script:
-    - python -m pip install .
-
-    - pytest
+#python-3.6:
+#  stage: test
+#  image: bilbydev/v2-dockerfile-test-suite-python36
+#  script:
+#    - python -m pip install .
+#
+#    - pytest
 
 # Tests run at a fixed schedule rather than on push
 scheduled-python-3.7: