Update CI workflow to install dependencies from requirements.txt

Author: imaginator

.github/workflows/ci.yml

@@ -25,6 +25,6 @@ jobs:
           path: ~/.cache 
           restore-keys: |
             mkdocs-material-
-      - run: pip install mkdocs-material git-revision-date-localized
+      - run: pip install -r requirements.txt
       - run: mkdocs gh-deploy --force