Update bg_replace.py

contrib/HumanSeg/bg_replace.py

 # coding: utf8
-# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserve.
+# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.