Bump copyright years in ikos CLI tool (c) notice (#249).

The copyright years reported by IKOS when executed with --version from
the command line does not include the latest changes.

This commit bumps the upper bound of the Copyright years in the notice
presented to users when the run the command-line tools, to include the
current year.

analyzer/python/ikos/args.py

@@ -126,7 +126,7 @@ def parse_argument(parser, name, choices, groups, default, value):
 class VersionAction(argparse.Action):
     def __call__(self, parser, namespace, values, option_string=None):
         print('ikos %s' % settings.VERSION)
-        print('Copyright (c) 2011-2019 United States Government as represented'
+        print('Copyright (c) 2011-2023 United States Government as represented'
               ' by the')
         print('Administrator of the National Aeronautics and Space '
               'Administration.')