docs: fix copyright string
@@ -51,7 +51,7 @@ master_doc = 'index'
# General information about the project.
project = 'gnpy'
-copyright = '2018, Telecom InfraProject - OOPT PSE Group'
+copyright = '2018 - 2021, Telecom Infra Project - OOPT PSE Group'
author = 'Telecom Infra Project - OOPT PSE Group'
# The language for content autogenerated by Sphinx. Refer to documentation
