Update sphinx.yml

Explicitly writing the sphinx build command within the steps

Author: mg-andrews

.github/workflows/sphinx.yml

@@ -14,7 +14,7 @@ jobs:
     - name: Install dependencies
       run: pip install -r requirements.txt
     - name: Build HTML
-      uses: ammaraskar/sphinx-action@master
+      run: sphinx-build -b html docs/source docs/build/html
     - name: Upload artifacts
       uses: actions/upload-artifact@v4
       with: