Fix usage of outdated module name (#784)

The module `openstack_image_manager.manage` was renamed to
`openstack_image_manager.main` in a previous commit.
A condition checking the module name was fixed to reflect this change.

Signed-off-by: Jan Horstmann <horstmann@osism.tech>

openstack_image_manager/main.py

@@ -119,7 +119,7 @@ def create_cli_args(
         logger.remove()
         logger.add(sys.stderr, format=log_fmt, level=level, colorize=True)
 
-        if __name__ == "__main__" or __name__ == "openstack_image_manager.manage":
+        if __name__ == "__main__" or __name__ == "openstack_image_manager.main":
             self.main()
 
     def read_image_files(self, return_all_images=False) -> list: