docs: update all-contributor badge (#22)

As seen in https://allcontributors.org/docs/en/bot/faq#all-contributors-badge-count-does-not-update

README.md

@@ -1,5 +1,7 @@
 # GitHub Sync
-[![All Contributors](https://img.shields.io/badge/all_contributors-3-orange.svg?style=flat-square)](#contributors)
+<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
+[![All Contributors](https://img.shields.io/badge/all_contributors-13-orange.svg?style=flat-square)](#contributors)
+<!-- ALL-CONTRIBUTORS-BADGE:END --> 
 
 A GitHub Action for syncing the current repository using **force push**. 
 
@@ -64,4 +66,4 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
 <!-- 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!
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!