Bump year to 2019

Author: Shnatsel

README.md

@@ -38,7 +38,7 @@ doesn't comply with the license.)
 
 Apache header:
 
-    Copyright 2018 Google LLC
+    Copyright 2019 Google LLC
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.