add fontawesome plugin install to workflow

.github/workflows/mkdocs.yml

@@ -31,7 +31,7 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-pip-
       - name: Install dependencies
-        run: python3 -m pip install mkdocs mkdocs-material
+        run: python3 -m pip install mkdocs mkdocs-material fontawesome_markdown
 
       - run: mkdocs build
 
@@ -39,4 +39,4 @@ jobs:
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./site
+          publish_dir: ./site