docs: update README.md [skip ci]

Author: allcontributors[bot]

README.md

@@ -1,4 +1,7 @@
 # `gren` 🤖
+<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
+[![All Contributors](https://img.shields.io/badge/all_contributors-1-orange.svg?style=flat-square)](#contributors-)
+<!-- ALL-CONTRIBUTORS-BADGE:END -->
 > Github release notes and changelog generator
 
 [![npm version](https://badge.fury.io/js/github-release-notes.svg)](https://badge.fury.io/js/github-release-notes)
@@ -212,3 +215,22 @@ gren init
 ```
 
 ### [See full documentation here](https://github-tools.github.io/github-release-notes)
+
+## Contributors ✨
+
+Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
+
+<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
+<!-- prettier-ignore-start -->
+<!-- markdownlint-disable -->
+<table>
+  <tr>
+    <td align="center"><a href="https://datitisev.me"><img src="https://avatars2.githubusercontent.com/u/6401250?v=4" width="100px;" alt=""/><br /><sub><b>David Sevilla Martín</b></sub></a><br /><a href="https://github.com/github-tools/github-release-notes/commits?author=datitisev" title="Documentation">📖</a></td>
+  </tr>
+</table>
+
+<!-- markdownlint-enable -->
+<!-- prettier-ignore-end -->
+<!-- ALL-CONTRIBUTORS-LIST:END -->
+
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!