Update actions/setup-python action to v6

Author: renovate[bot]

.github/workflows/Certora.yaml

@@ -30,7 +30,7 @@ jobs:
         run: forge install
 
       - name: Install python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.10"
           cache: "pip"