Update README.md

Author: Onatcer

README.md

@@ -78,6 +78,10 @@ Configures what state of the toggle button should be shown to the user.
 -   `currentState` - Shows the state that is currently applied to the website.
 -   `newState` - Shows the state that will be applied when the user clicks the button.
 
+## Contribution Guidelines
+
+Please open an issue and wait for one of the Maintainers to approve it until you open a merge request. 
+
 ## Credits
 
 This project is heavily inspired by Aral Balkan who [wrote down this idea to implement dark mode in a few lines of CSS using CSS Filters](https://ar.al/2021/08/24/implementing-dark-mode-in-a-handful-of-lines-of-css-with-css-filters/).