Remove stale API reference link

Author: ddworak

README.md

@@ -3,8 +3,6 @@
 [![Continuous Integration](https://github.com/AVSystem/scala-commons/actions/workflows/ci.yml/badge.svg)](https://github.com/AVSystem/scala-commons/actions/workflows/ci.yml)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.avsystem.commons/commons-core_2.12/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.avsystem.commons/commons-core_2.13)
 
-**[API reference](http://avsystem.github.io/scala-commons/api/com/avsystem/commons/index.html)**
-
 **NOTE** This library is available to the public but it's mostly used internally at AVSystem. Therefore, API may frequently change in an incompatible way.
 
 ## Modules and features