Update documentation.yml to auto add all changes to new commit

.github/workflows/documentation.yml

@@ -34,6 +34,7 @@ jobs:
       run: |
         pip install sphinx sphinx_rtd_theme nbsphinx ipython jupyter
         cd docs
+        make clean
         make html
 
     - name: Commit documentation changes to gh-pages
@@ -44,7 +45,8 @@ jobs:
         cp -r ../_build/html/* .
         git config --local user.email "action@github.com"
         git config --local user.name "GitHub Action"
-        git commit -m "Upload documentation from latest commit" -a
+        git add .
+        git commit -m "Upload documentation from latest commit"
 
     - name: Push changes to gh-pages
       uses: ad-m/github-push-action@master