update python version

.github/workflows/build.yml

@@ -124,10 +124,10 @@ jobs:
         ndk-version: r25c
         local-cache: true
 
-    - name: Set up Python 3.8
+    - name: Set up Python 3.9
       uses: actions/setup-python@v4
       with:
-        python-version: 3.8
+        python-version: 3.9
 
     - name: install dependencies
       run: |