bump google.golang.org/grpc v1.20.1

full diff: https://github.com/grpc/grpc-go/compare/v1.12.2...v1.20.1

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/google.golang.org/grpc/internal/transport/log.go

@@ -0,0 +1,44 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// This file contains wrappers for grpclog functions.
+// The transport package only logs to verbose level 2 by default.
+
+package transport
+
+import "google.golang.org/grpc/grpclog"
+
+const logLevel = 2
+
+func infof(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Infof(format, args...)
+	}
+}
+
+func warningf(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Warningf(format, args...)
+	}
+}
+
+func errorf(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Errorf(format, args...)
+	}
+}