Update vulnerabilities/improver.py

Co-authored-by: Philippe Ombredanne <pombredanne@gmail.com>

Author: Hritik14

vulnerabilities/improver.py

@@ -85,7 +85,7 @@ def qualified_name(cls):
         """
         Fully qualified name prefixed with the module name of the improver used in logging.
         """
-        return f"{self.__module__}.{self.__qualname__}"
+        return f"{cls.__module__}.{cls.__qualname__}"
 
     @property
     def interesting_advisories(self) -> QuerySet: