Merge pull request swiftlang#80923 from bnbarham/update-rebranch-aliases

Add the current stable branch to the list of rebranch aliases

Author: bnbarham

utils/update_checkout/update-checkout-config.json

@@ -443,7 +443,7 @@
             }
         },
         "rebranch": {
-            "aliases": ["rebranch"],
+            "aliases": ["rebranch", "stable/20250402"],
             "repos": {
                 "llvm-project": "stable/20250402",
                 "swift-llvm-bindings": "stable/20240723",