Merge pull request #5418 from dotnet/backport/pr-5417-to-release/9.0

[release/9.0] [release/8.0] Add merge flow configurations for release branches

Author: merriemcgaw

github-merge-flow.jsonc

@@ -0,0 +1,17 @@
+// IMPORTANT: This file is read by the merge flow from main branch only. 
+{
+    "merge-flow-configurations": {
+        "release/8.0":{
+            "MergeToBranch": "release/9.0",
+            "ExtraSwitches": "-QuietComments"
+        },
+        "release/9.0":{
+            "MergeToBranch": "release/10.0",
+            "ExtraSwitches": "-QuietComments"
+        },
+        "release/10.0":{
+            "MergeToBranch": "main",
+            "ExtraSwitches": "-QuietComments"
+        }
+    }
+}