[ci/cd] parallel tests on multiple python versions

.gitlab-ci.yml

@@ -31,13 +31,21 @@ stages:
   - test
   - build
 
-test:
-  stage: test
-  script:
+.before_script_template: &test
+  before_script:
     - apt-get update && apt-get -y install python3-venv
     - python3 -V  # Print out python version for debugging
     - pip3 install pipenv
     - pipenv install  --dev --skip-lock
+
+test:
+  image: python:${PYVERSION}-bullseye
+  stage: test
+  <<: *test
+  parallel:
+    matrix:
+      - PYVERSION: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+  script:
     - pipenv run pytest --version
     - PYTHONPATH=./tests/ pipenv run pytest -v ./tests
     - pipenv run halfapi --version