make package builds work on kokoro
diff --git a/src/csharp/build_packages_dotnetcli.sh b/src/csharp/build_packages_dotnetcli.sh
index e3f8463..1b73614 100755
--- a/src/csharp/build_packages_dotnetcli.sh
+++ b/src/csharp/build_packages_dotnetcli.sh
@@ -21,11 +21,17 @@
 
 # Collect the artifacts built by the previous build step
 mkdir -p nativelibs
+# Jenkins flow (deprecated)
 cp -r $EXTERNAL_GIT_ROOT/platform={windows,linux,macos}/artifacts/csharp_ext_* nativelibs || true
+# Kokoro flow
+cp -r $EXTERNAL_GIT_ROOT/input_artifacts/csharp_ext_* nativelibs || true
 
 # Collect protoc artifacts built by the previous build step
 mkdir -p protoc_plugins
+# Jenkins flow (deprecated)
 cp -r $EXTERNAL_GIT_ROOT/platform={windows,linux,macos}/artifacts/protoc_* protoc_plugins || true
+# Kokoro flow
+cp -r $EXTERNAL_GIT_ROOT/input_artifacts/protoc_* protoc_plugins || true
 
 dotnet restore Grpc.sln