Change python version in automated testing

.github/workflows/python-package-conda.yml

@@ -10,10 +10,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - name: Set up Python 3.10
+    - name: Set up Python 3.9
       uses: actions/setup-python@v3
       with:
-        python-version: 3.10
+        python-version: 3.9.7
     - name: Add conda to system path
       run: |
         # $CONDA is an environment variable pointing to the root of the miniconda directory