Fix link to test.kt in README.md

Author: christxph

README.md

@@ -2,7 +2,7 @@
 
 Unsigned operators and boxed types (`Ubyte`, `Uint`, `Ulong` and `Ushort`) for unsigned support.
 
-To have a quick idea what this library offers, take a look at the [tests](https://github.com/kotlin-graphics/kotlin-unsigned/blob/master/src/test/kotlin/unsigned/unsigned.kt)
+To have a quick idea what this library offers, take a look at the [tests](https://github.com/kotlin-graphics/kotlin-unsigned/blob/master/src/test/kotlin/unsigned/test.kt)
 
 ### How to get it: