Update config.py

Syntax fix for unterminated single quote

opendm/config.py

@@ -276,7 +276,7 @@ def config(argv=None, parser=None):
                         'A memory and processor hungry change relative to the default behavior if set to true. '
                         'Ordinarily, GSD estimates are used to cap the maximum resolution of image outputs and resizes images when necessary, resulting in faster processing and lower memory usage. '
                         'Since GSD is an estimate, sometimes ignoring it can result in slightly better image output quality. '
-                        'Never set --ignore-gsd to true unless you are positive you need it, and even then: don't use it. Default: %(default)s')
+                        'Never set --ignore-gsd to true unless you are positive you need it, and even then: do not use it. Default: %(default)s')
     
     parser.add_argument('--no-gpu',
                     action=StoreTrue,