codec/codecgen: added copyright info

codec/codecgen/z.go

@@ -1,3 +1,6 @@
+// Copyright (c) 2012-2018 Ugorji Nwoke. All rights reserved.
+// Use of this source code is governed by a MIT license found in the LICENSE file.
+
 package main
 
 const genCodecPath = "github.com/ugorji/go/codec"