Merge branch 'run-tests' into 'main'

Update .gitlab-ci.yml

See merge request !2

.gitlab-ci.yml

+run_tests:
+  image: "python:$VERSION"
+  script:
+    - pip install -e .[dev]
+    - export PYTHONPATH="$(pwd)"
+    - coverage run --source . run_tests.py
+    - coverage report -m
+  parallel:
+    matrix:
+      - VERSION: ['3.8', '3.11']
+
+
+
 upload:
   stage: deploy
   rules: