Merge pull request #1176 from firesim/backports-to-stable

Backports go to stable branch, which should generally point to the la…

.mergify.yml

@@ -1,7 +1,4 @@
 pull_request_rules:
-  # For FireSim version 1.x.y, here let x = minor, y = patch
-  # Only support backporting to the last minor release branch.
-  # This rule will need to be updated on minor releases.
   - name: backport to latest minor release
     conditions:
       - merged
@@ -10,7 +7,7 @@ pull_request_rules:
     actions:
       backport:
         branches:
-          - 1.13.x
+          - stable
         ignore_conflicts: True
         label_conflicts: "bp-conflict"
       label: