Add repology badge (#2367)

So we can see which distributions package raylib.
And in which version they are.

README.md

@@ -14,6 +14,7 @@ Ready to learn? Jump to [code examples!](https://www.raylib.com/examples.html)
 
 [![GitHub contributors](https://img.shields.io/github/contributors/raysan5/raylib)](https://github.com/raysan5/raylib/graphs/contributors)
 [![GitHub All Releases](https://img.shields.io/github/downloads/raysan5/raylib/total)](https://github.com/raysan5/raylib/releases)
+[![Packaging status](https://repology.org/badge/tiny-repos/raylib.svg)](https://repology.org/project/raylib/versions)
 [![GitHub commits since tagged version](https://img.shields.io/github/commits-since/raysan5/raylib/4.0.0)](https://github.com/raysan5/raylib/commits/master)
 [![License](https://img.shields.io/badge/license-zlib%2Flibpng-blue.svg)](LICENSE)