Update .mergify.yml (#5958)

Adds 8.17.0 to mergify and updates 8.16.

Author: jmikell821

.mergify.yml

@@ -13,6 +13,20 @@ pull_request_rules:
             git merge upstream/{{base}}
             git push upstream {{head}}
             ```
+  - name: backport patches to 8.17 branch
+    conditions:
+      - merged
+      - base=main
+      - label=v8.17.0
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "8.x"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
+        labels:
+          - backport
   - name: backport patches to 8.16 branch
     conditions:
       - merged
@@ -23,7 +37,7 @@ pull_request_rules:
         assignees:
           - "{{ author }}"
         branches:
-          - "8.x"
+          - "8.16"
         title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
         labels:
           - backport