Update index.rst (#8708)

Author: MapleCCC

doc/en/index.rst

@@ -129,8 +129,8 @@ Tidelift will coordinate the fix and disclosure.
 License
 -------
 
-Copyright Holger Krekel and others, 2004-2020.
+Copyright Holger Krekel and others, 2004-2021.
 
 Distributed under the terms of the `MIT`_ license, pytest is free and open source software.
 
-.. _`MIT`: https://github.com/pytest-dev/pytest/blob/master/LICENSE
+.. _`MIT`: https://github.com/pytest-dev/pytest/blob/main/LICENSE