Latest and greatest (3.12.0) (#1174)

Author: AA-Turner

include/release-cycle.json

@@ -10,7 +10,7 @@
   "3.12": {
     "branch": "3.12",
     "pep": 693,
-    "status": "prerelease",
+    "status": "stable",
     "first_release": "2023-10-02",
     "end_of_life": "2028-10",
     "release_manager": "Thomas Wouters"