Update copyright year to 2021 (#793)

seisman · web-flow · commit a618a8d9e40a · 2021-01-15T10:37:08.000-05:00
diff --git a/LICENSE.txt b/LICENSE.txt
@@ -1,4 +1,4 @@
-Copyright (c) 2017-2020 The PyGMT Developers
+Copyright (c) 2017-2021 The PyGMT Developers
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-Copyright (c) 2017-2020 The PyGMT Developers`
	`1`	`+Copyright (c) 2017-2021 The PyGMT Developers`
`2`	`2`	`All rights reserved.`
`3`	`3`
`4`	`4`	`Redistribution and use in source and binary forms, with or without modification,`