upgrade third_party/protobufs to 3.0.0-beta-1
diff --git a/src/csharp/.gitignore b/src/csharp/.gitignore
index 48365e3..deac550 100644
--- a/src/csharp/.gitignore
+++ b/src/csharp/.gitignore
@@ -4,6 +4,9 @@
 test-results
 packages
 Grpc.v12.suo
+Grpc.sdf
+
 TestResult.xml
 /TestResults
+.vs/
 *.nupkg