Add UTM attribution to the Github profile link

Author: e1himself

README.md

@@ -55,5 +55,5 @@ final class MyServiceContainer implements ContainerInterface
 [1]: https://www.php-fig.org/psr/psr-11/
 [2]: https://en.wikipedia.org/wiki/Null_object_pattern
 [3]: https://getcomposer.org/
-[4]: https://github.com/e1himself
+[4]: https://github.com/e1himself?utm_source=web&utm_medium=github&utm_campaign=technically/null-container
 [status-badge]: https://github.com/technically-php/null-container/actions/workflows/test.yml/badge.svg