NFS-1239: Link updated

Author: cornelius-behrend

README.md

@@ -1,6 +1,6 @@
 # Plugin SDK for Java
 
-If you are developing your own plugin for your Staffbase app we describe the authentication flow of a plugin at https://developers.staffbase.com/api/plugin-sso/. While this documentation just covers the conceptual ideas of the interface of plugins though – the so called Plugin SSO – we want to provide a library to help you develop your first plugin for Staffbase even faster. This SDK provides the basic functionality to parse and verify a provided token for Java.
+If you are developing your own plugin for your Staffbase app we describe the authentication flow of a plugin at https://developers.staffbase.com/guide/customplugin-overview/. While this documentation just covers the conceptual ideas of the interface of plugins though – the so called Plugin SSO – we want to provide a library to help you develop your first plugin for Staffbase even faster. This SDK provides the basic functionality to parse and verify a provided token for Java.
 
 ## Installation