Use Python 3.11 in CI (mozilla#2736)

Author: marco-c

.taskcluster.yml

@@ -70,7 +70,7 @@ tasks:
       else: generic-worker-ubuntu-24-04
 
     taskboot_image: "mozilla/taskboot:0.4.1"
-    python_image: "python:3.10"
+    python_image: "python:3.11"
   in:
     $if: '(tasks_for == "github-push" && (head_branch == "master" || head_branch == "production" || head_branch == "testing")) || (tasks_for == "github-pull-request" && event["action"] in ["opened", "reopened", "synchronize"])'
     then: