Add system dependencies installation step

Author: gletort

.github/workflows/ci.yml

@@ -33,7 +33,8 @@ jobs:
           restore-keys: |
             mkdocs-material-
       - run: pip install mkdocs-material 
-
+      - name: Install system deps
+        run: sudo apt-get update && sudo apt-get install -y libegl1-mesa libopengl0
       - run: pip install pdoc
       - run: pip install -e .
       - run: pdoc epicure -o docs/api