Ruby wrapping of core credentials API change.
diff --git a/src/ruby/bin/noproto_client.rb b/src/ruby/bin/noproto_client.rb
index 390a9c5..3aa1187 100755
--- a/src/ruby/bin/noproto_client.rb
+++ b/src/ruby/bin/noproto_client.rb
@@ -68,7 +68,7 @@
 
 def test_creds
   certs = load_test_certs
-  GRPC::Core::Credentials.new(certs[0])
+  GRPC::Core::ChannelCredentials.new(certs[0])
 end
 
 def main