fix(mergify): remove auto-update rule that adds merge commits

The update action always creates merge commits when bringing PRs
up to date with main. The rebase action that previously handled
this correctly is deprecated for fork PRs after July 1, 2026.

Remove the auto-update rule entirely. Contributors can use the
existing conflict notification and manual @mergify rebase when
needed.

Closes: #1069
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Lalatendu Mohanty <lmohanty@redhat.com>

Author: LalatenduMohanty

.mergify.yml

@@ -78,17 +78,6 @@ pull_request_rules:
       merge:
         method: merge
 
-  - name: Auto-update approved PRs that are behind
-    conditions:
-      - "-draft"
-      - "-conflict"
-      - "#commits-behind>0"
-      - "base=main"
-      - "#approved-reviews-by>=1"
-      - "author!=dependabot[bot]"
-    actions:
-      update:
-
   - name: Ping author on conflicts
     conditions:
       - "conflict"