README: remove the "most popular" claim

This is, unfortunately, not the case anymore.

Closes #2209

README.md

@@ -91,10 +91,6 @@ ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).
     * [Troubleshooter](https://arduinojson.org/v7/troubleshooter/)
     * [Book](https://arduinojson.org/book/)
     * [Changelog](CHANGELOG.md)
-* Vibrant user community
-    * Most popular of all Arduino libraries on [GitHub](https://github.com/search?o=desc&q=arduino+library&s=stars&type=Repositories)
-    * [Used in hundreds of projects](https://www.hackster.io/search?i=projects&q=arduinojson)
-    * [Responsive support](https://github.com/bblanchon/ArduinoJson/issues?q=is%3Aissue+is%3Aclosed)
 
 ## Quickstart