Repurpose 'backport-iron' to 'backport-kilted' for mergify bot (#3647)

Author: nbbrooks

.github/mergify.yml

@@ -8,23 +8,23 @@ pull_request_rules:
         branches:
           - humble
 
-  - name: backport to iron at reviewers discretion
+  - name: backport to jazzy at reviewers discretion
     conditions:
       - base=main
-      - "label=backport-iron"
+      - "label=backport-jazzy"
     actions:
       backport:
         branches:
-          - iron
+          - jazzy
 
-  - name: backport to jazzy at reviewers discretion
+  - name: backport to kilted at reviewers discretion
     conditions:
       - base=main
-      - "label=backport-jazzy"
+      - "label=backport-kilted"
     actions:
       backport:
         branches:
-          - jazzy
+          - kilted
 
   - name: ask to resolve conflict
     conditions: