docs: update README.md [skip ci]

Author: allcontributors[bot]

README.md

@@ -3,7 +3,8 @@
 [![image](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![image](https://badge.fury.io/py/s2fft.svg)](https://badge.fury.io/py/s2fft)
 [![image](http://img.shields.io/badge/arXiv-2311.14670-orange.svg?style=flat)](https://arxiv.org/abs/2311.14670)<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-7-orange.svg?style=flat-square)](#contributors-)<!-- ALL-CONTRIBUTORS-BADGE:END --> 
+[![All Contributors](https://img.shields.io/badge/all_contributors-8-orange.svg?style=flat-square)](#contributors-)
+<!-- ALL-CONTRIBUTORS-BADGE:END --> 
 [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1YmJ2ljsF8HBvhPmD4hrYPlyAKc4WPUgq?usp=sharing)
 <!-- [![image](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black) -->
 
@@ -167,6 +168,9 @@ key](https://allcontributors.org/docs/en/emoji-key)):
       <td align="center" valign="top" width="14.28%"><a href="http://flanusse.net"><img src="https://avatars.githubusercontent.com/u/861591?v=4?s=100" width="100px;" alt="Francois Lanusse"/><br /><sub><b>Francois Lanusse</b></sub></a><br /><a href="https://github.com/astro-informatics/s2fft/commits?author=EiffL" title="Code">💻</a> <a href="https://github.com/astro-informatics/s2fft/issues?q=author%3AEiffL" title="Bug reports">🐛</a></td>
       <td align="center" valign="top" width="14.28%"><a href="https://github.com/eltociear"><img src="https://avatars.githubusercontent.com/u/22633385?v=4?s=100" width="100px;" alt="Ikko Eltociear Ashimine"/><br /><sub><b>Ikko Eltociear Ashimine</b></sub></a><br /><a href="https://github.com/astro-informatics/s2fft/commits?author=eltociear" title="Documentation">📖</a></td>
     </tr>
+    <tr>
+      <td align="center" valign="top" width="14.28%"><a href="https://github.com/kmulderdas"><img src="https://avatars.githubusercontent.com/u/33317219?v=4?s=100" width="100px;" alt="Kevin Mulder"/><br /><sub><b>Kevin Mulder</b></sub></a><br /><a href="https://github.com/astro-informatics/s2fft/issues?q=author%3Akmulderdas" title="Bug reports">🐛</a></td>
+    </tr>
   </tbody>
 </table>