[DOC] Update copyright

Author: xuyxu

docs/conf.py

@@ -19,7 +19,7 @@
 
 # -- Project information -----------------------------------------------------
 project = 'Ensemble-PyTorch'
-copyright = '2020, Ensemble-PyTorch Developers'
+copyright = '2021, Ensemble-PyTorch Developers'
 author = 'Ensemble-PyTorch Developers'
 
 # The master toctree document.