feat: experimenting a custom testing image

.gitlab/ci/test.gitlab-ci.yml

@@ -1,14 +1,7 @@
 test:
   stage: test
-  image: python:3.7
+  image: slumber/blender-addon-testing:latest
   script:
-    - git submodule init
-    - git submodule update
-    - apt-get update
-    # install blender to get all required dependencies
-    # TODO: indtall only dependencies
-    - apt install -f -y blender  
-    - python -m pip install blender-addon-tester
     - python scripts/test_addon.py
 
   only: