remove support by yourkit

Author: andimarek

README.md

@@ -34,7 +34,3 @@ take the time to read it.
 Copyright (c) 2015, Andreas Marek and [Contributors](https://github.com/graphql-java/graphql-java/graphs/contributors)
 
 ### Supported by
-
-![YourKit](https://www.yourkit.com/images/yklogo.png)
-
-[YourKit](https://www.yourkit.com/) supports this project by providing the YourKit Java Profiler.