build: update labels to match standardized labels

Author: josephperrott

.ng-dev/pull-request.mts

@@ -13,7 +13,7 @@ export const pullRequest: PullRequestConfig = {
     default: 'squash',
     labels: [{pattern: 'preserve commits', method: 'rebase'}],
   },
-  mergeReadyLabel: 'merge ready',
-  commitMessageFixupLabel: 'commit message fixup',
-  caretakerNoteLabel: 'caretaker note',
+  mergeReadyLabel: 'action: merge',
+  commitMessageFixupLabel: 'merge: fix commit message',
+  caretakerNoteLabel: 'merge: caretaker note',
 };