push nuget on merge only

Author: vilinski

.github/workflows/dotnet.yml

@@ -105,6 +105,7 @@ jobs:
     #     path: nupkg
 
   push_chdb:
+    if: github.event.pull_request.merged
     name: Push chdb
     needs: build_chdb
     runs-on: ubuntu-latest
@@ -133,6 +134,7 @@ jobs:
 
 
   push_tool:
+    if: github.event.pull_request.merged
     name: Push chdb-tool
     needs: push_chdb
     runs-on: ubuntu-latest