docs: Follow-up to #959, more copyright year bumps.

LICENSE

@@ -1,4 +1,4 @@
-"iperf, Copyright (c) 2014-2019, The Regents of the University of California,
+"iperf, Copyright (c) 2014-2020, The Regents of the University of California,
 through Lawrence Berkeley National Laboratory (subject to receipt of any 
 required approvals from the U.S. Dept. of Energy).  All rights reserved."
 

docs/conf.py

@@ -45,7 +45,7 @@ master_doc = 'index'
 
 # General information about the project.
 project = u'iperf3'
-copyright = u'2014-2019, ESnet'
+copyright = u'2014-2020, ESnet'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the