Added JetBrains OSS badge

Author: shanshin

README.md

@@ -1,6 +1,7 @@
 # Kover
 
 [![Kotlin Beta](https://kotl.in/badges/beta.svg)](https://kotlinlang.org/docs/components-stability.html)
+[![official JetBrains project](https://jb.gg/badges/official.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
 [![GitHub license](https://img.shields.io/badge/license-Apache%20License%202.0-blue.svg?style=flat)](https://www.apache.org/licenses/LICENSE-2.0)
 
 Kover is a set of solutions for collecting test coverage of Kotlin code compiled for JVM and Android platforms.