Switch to argparse for management command argument parsing

course_discovery/apps/courses/management/commands/refresh_all_courses.py

 import logging
-from optparse import make_option
 
 from django.core.management import BaseCommand, CommandError
 
@@ -11,12 +10,13 @@ logger = logging.getLogger(__name__)
 class Command(BaseCommand):
     help = 'Refresh course data from external sources.'
 
-    option_list = BaseCommand.option_list + (
-        make_option('--access_token',
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--access_token',
             action='store',
             dest='access_token',
             default=None,
-                    help='OAuth2 access token used to authenticate API calls.'),
+            help='OAuth2 access token used to authenticate API calls.'
         )
 
     def handle(self, *args, **options):