TST: Add Python 3.7 to unittest pipeline

.gitlab-ci.yml

@@ -134,16 +134,22 @@ unittest_py39:
     - python3 -c "import caosdb; print('CaosDB Version:', caosdb.__version__)"
     - tox
 
-unittest_py38:
+unittest_py37:
   tags: [docker]
   stage: unittest
-  image: python:3.8
+  image: python:3.7
   script: &python_test_script
     - pip install nose pandas pytest pytest-cov gitignore-parser openpyxl>=3.0.7 xlrd==1.2 h5py
     - pip install git+https://gitlab.indiscale.com/caosdb/src/caosdb-pylib.git@dev
     - pip install .
     - pytest --cov=caosadvancedtools unittests
 
+unittest_py38:
+  tags: [docker]
+  stage: unittest
+  image: python:3.8
+  script: *python_test_script
+
 unittest_py310:
   tags: [docker]
   stage: unittest