Update years in opencv license according to the original repo (#477)

Author: sergregory

Diff for: LICENSE-3RD-PARTY.txt

@@ -10,13 +10,13 @@ copy or use the software.
                For Open Source Computer Vision Library
                        (3-clause BSD License)
 
-Copyright (C) 2000-2020, Intel Corporation, all rights reserved.
+Copyright (C) 2000-2021, Intel Corporation, all rights reserved.
 Copyright (C) 2009-2011, Willow Garage Inc., all rights reserved.
 Copyright (C) 2009-2016, NVIDIA Corporation, all rights reserved.
 Copyright (C) 2010-2013, Advanced Micro Devices, Inc., all rights reserved.
-Copyright (C) 2015-2016, OpenCV Foundation, all rights reserved.
+Copyright (C) 2015-2021, OpenCV Foundation, all rights reserved.
 Copyright (C) 2015-2016, Itseez Inc., all rights reserved.
-Copyright (C) 2019-2020, Xperience AI, all rights reserved.
+Copyright (C) 2019-2021, Xperience AI, all rights reserved.
 Third party copyrights are property of their respective owners.
 
 Redistribution and use in source and binary forms, with or without modification,