React to runtime release branch rename (#25026)

Author: Tratcher

.github/workflows/runtime-sync.yml

@@ -28,7 +28,7 @@ jobs:
         # Test this script using changes in a fork 
         repository: 'dotnet/runtime'
         path: runtime
-        ref: release/5.0-rc1
+        ref: release/5.0
     - name: Copy
       shell: cmd
       working-directory: .\runtime\src\libraries\Common\src\System\Net\Http\aspnetcore\