Merge pull request #190 from alan-turing-institute/fix-deployment-2

Add dep mkdocs-material-extensions to ci.yml

Author: thobson88

.github/workflows/ci.yml

@@ -25,5 +25,5 @@ jobs:
           path: .cache
           restore-keys: |
             mkdocs-material-
-      - run: pip install mkdocs-material mkdocs-awesome-pages-plugin
+      - run: pip install mkdocs-material mkdocs-material-extensions mkdocs-awesome-pages-plugin
       - run: mkdocs gh-deploy --force