Corrected workflow to correct syntax highlighting

Author: davistdaniel

.github/workflows/deploy-docs.yml

@@ -21,12 +21,13 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y pandoc
-          
+
       - name: Install dependencies
         run: |
           pip install .
           pip install sphinx
           pip install nbsphinx
+          pip install pygments ipython --upgrade
 
       - name: Build documentation
         run: |