docs: remove disclaimer

Author: idleberg

README.md

@@ -27,9 +27,6 @@ gulp.task('lint', done => {
 });
 ```
 
-> [!IMPORTANT]
-> This plugin is now pure ESM. [Read how to migrate your `Gulpfile`](https://gist.github.com/noraj/007a943dc781dc8dd3198a29205bae04). Alternatively, you can continue using an *unsupported* 1.x version.
-
 ### Options
 
 #### `options.mimeType`