fix: Install dependencies from requirements file.

Workflow will now adjust when dependencies are added to docs/requirements.txt

.github/workflows/deploy-ghpages.yml

@@ -24,5 +24,5 @@ jobs:
           path: .cache
           restore-keys: |
             mkdocs-material-
-      - run: pip install mkdocs-material 
+      - run: pip install -r docs/requirements.txt
       - run: mkdocs gh-deploy --force --config-file docs/mkdocs.yml