doc: add Hemanth HM mention to v21.7.0 changelog

PR-URL: #52008
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>

doc/changelogs/CHANGELOG_V21.md

@@ -61,7 +61,7 @@ const errorMessage = styleText('red', 'Error! Error!');
 console.log(errorMessage);
 ```
 
-Contributed by Rafael Gonzaga in [#51850](https://github.com/nodejs/node/pull/51850).
+Contributed by Rafael Gonzaga and Hemanth HM in [#51850](https://github.com/nodejs/node/pull/51850).
 
 ### Loading and parsing environment variables