[3.7] Bump copyright years to 2019. (GH-11406)

(cherry picked from commit 9a69ae8a78785105ded02b083b2e5cd2dd939307)
diff --git a/Doc/copyright.rst b/Doc/copyright.rst
index 540ff5e..393a1f0 100644
--- a/Doc/copyright.rst
+++ b/Doc/copyright.rst
@@ -4,7 +4,7 @@
 
 Python and this documentation is:
 
-Copyright © 2001-2018 Python Software Foundation. All rights reserved.
+Copyright © 2001-2019 Python Software Foundation. All rights reserved.
 
 Copyright © 2000 BeOpen.com. All rights reserved.