Update Python version in workflow to 3.13

Author: theroyakash

.github/workflows/app.yml

@@ -22,10 +22,10 @@ jobs:
     - uses: actions/checkout@v2
 
     # Install dependencies
-    - name: Set up Python 3.9
+    - name: Set up Python 3.13
       uses: actions/setup-python@v1
       with:
-        python-version: 3.9
+        python-version: 3.13
 
     - name: Install dependencies
       run: |