Prepare release using 3.x instead of 3.8

Author: Pierre-Sassoulas

.github/workflows/prepare-release-pr.yml

@@ -34,7 +34,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v5
       with:
-        python-version: "3.8"
+        python-version: "3.x"
 
     - name: Install dependencies
       run: |