Fix package name in GitHub Actions workflow

Author: StuartFarmer

.github/workflows/deploy-docs.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install mkdocs-material mkdocstrings[python] mermaid2
+          pip install "mkdocs-material" "mkdocstrings[python]" "mkdocs-mermaid2-plugin"
           
       - name: Build documentation
         run: mkdocs build