added an installation of libgl1-mesa-glx for gitlab-ci

.gitlab-ci.yml

@@ -33,6 +33,8 @@ webui:
     - python -V
     - python -m venv env
     - source env/bin/activate
+    - apt-get update
+    - apt-get install -y libgl1-mesa-glx
     - pip install -r requirements.txt
     - pip install -r requirements.dev.txt
   script: