Update main.yml

try with python 3.9

Author: mihersch

.github/workflows/main.yml

@@ -14,10 +14,10 @@ jobs:
     - uses: actions/checkout@v2
 
     # Install dependencies
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v1
       with:
-        python-version: 3.10
+        python-version: 3.9
 
     - name: Install dependencies
       run: |
@@ -44,10 +44,10 @@ jobs:
     - uses: actions/checkout@v2
 
     # Install dependencies
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v1
       with:
-        python-version: 3.10
+        python-version: 3.9
 
     - name: Install dependencies
       run: |