ci(mergify): upgrade configuration to current format

Author: mergify[bot]

.mergify.yml

@@ -2,8 +2,8 @@ commands_restrictions:
   backport:
     conditions:
       - or:
-        - sender-permission>=write
-        - sender=github-actions[bot]
+          - sender-permission>=write
+          - sender=github-actions[bot]
 queue_rules:
   - name: default
     merge_method: squash
@@ -73,17 +73,6 @@ pull_request_rules:
         message: |
           This pull request has been automatically closed by Mergify.
           There are some other up-to-date pull requests.
-  - name: delete upstream branch after merging changes on .go-version or it's closed
-    conditions:
-      - or:
-          - merged
-          - closed
-      - and:
-          - label=automation
-          - head~=^update-go-version
-          - files~=^\.go-version$
-    actions:
-      delete_head_branch:
   - name: automatic approval for mergify pull requests with changes in bump-rules
     conditions:
       - author=mergify[bot]
@@ -109,17 +98,6 @@ pull_request_rules:
     actions:
       queue:
         name: default
-  - name: delete upstream branch with changes on ^.mergify.yml that has been merged or closed
-    conditions:
-      - or:
-          - merged
-          - closed
-      - and:
-          - label=automation
-          - head~=^add-backport-next.*
-          - files~=^\.mergify\.yml$
-    actions:
-      delete_head_branch:
   - name: notify the backport has not been merged yet
     conditions:
       - -merged