doc: update doc footer copyright year

Update the documentation footer copyright year.

Signed-off-by: Mikkel Jakobsen <[email protected]>

Author: Mikkel Jakobsen

doc/conf.py

@@ -75,7 +75,7 @@
 
 # General information about the project.
 project = u'Zephyr Project'
-copyright = u'2015-2020 Zephyr Project members and individual contributors'
+copyright = u'2015-2021 Zephyr Project members and individual contributors'
 author = u'The Zephyr Project'
 
 # The following code tries to extract the information by reading the Makefile,