Update onnxrt action (#1545)

Declare OS type in action

.github/workflows/sync-onnxrt-main.yaml

 name: Onnxruntime main weekly sync
 on:
   schedule:
-    - cron: "0 4 * * 1"
+    - cron: "05 17 * * 1"
 
 jobs:
+  runs-on: ubuntu-latest
   sync:
     steps:
       - uses: actions/checkout@v3