Update copyright notice in docs

Author: amorison

docs/conf.py

@@ -79,7 +79,7 @@ def __getattr__(cls, name):
 
 # General information about the project.
 project = 'StagPy'
-copyright = '2015 - 2018, Adrien Morison, Martina Ulvrova, Stéphane Labrosse'
+copyright = '2015 - 2019, Adrien Morison, Martina Ulvrova, Stéphane Labrosse'
 author = 'Adrien Morison, Martina Ulvrova, Stéphane Labrosse'
 
 # The version info for the project you're documenting, acts as replacement for