Update backport config to fix check

Author: brianseeders

.backportrc.json

@@ -3,8 +3,7 @@
   "targetBranchChoices" : [ "main", "8.x", "8.16", "8.15", "8.14", "8.13", "8.12", "8.11", "8.10", "8.9", "8.8", "8.7", "8.6", "8.5", "8.4", "8.3", "8.2", "8.1", "8.0", "7.17", "6.8" ],
   "targetPRLabels" : [ "backport" ],
   "branchLabelMapping" : {
-    "^v9.0.0$" : "main",
-    "^v8.17.0$" : "8.x",
+    "^v8.16.1$" : "main",
     "^v(\\d+).(\\d+).\\d+(?:-(?:alpha|beta|rc)\\d+)?$" : "$1.$2"
   }
-}
+}