TST: Add Python 3.7 to pipeline

.gitlab-ci.yml

@@ -54,6 +54,13 @@ pylint:
   allow_failure: true
 
 # run unit tests
+unittest_py3.7:
+  tags: [ docker ]
+  stage: test
+  needs: [ ]
+  image: python:3.7
+  script: *python_test_script
+
 unittest_py3.8:
   tags: [ docker ]
   stage: test
@@ -62,7 +69,7 @@ unittest_py3.8:
   script: &python_test_script
     # Python docker has problems with tox and pip so use plain pytest here
     - touch ~/.pycaosdb.ini
-    - pip install nose pytest pytest-cov python-dateutil jsonschema==4.0.1
+    - pip install nose pytest pytest-cov python-dateutil jsonschema>=4.4.0
     - pip install .
     - python -m pytest unittests