Specify Sphinx version for build_and_deploy action. (#2802)

Author: atmyers

.github/workflows/docs.yml

@@ -18,7 +18,8 @@ jobs:
       - name: Dependencies
         run: |
           .github/workflows/dependencies/documentation.sh
-          python3 -m pip install sphinx sphinx_rtd_theme breathe
+          python3 -m pip install --upgrade pip
+          python3 -m pip install sphinx==4.5.0 sphinx_rtd_theme breathe
           python3 -m pip install -I docutils==0.16  # Downgrade docutils so that bullet points render properly with Sphinx
 
       - name: Install and Build