link to error prone documentation

Signed-off-by: olivier lamy <[email protected]>

Author: olamy

README.md

@@ -6,3 +6,8 @@ Plexus-Compiler
 [![Build Status](https://travis-ci.org/codehaus-plexus/plexus-compiler.svg?branch=master)](https://travis-ci.org/codehaus-plexus/plexus-compiler)
 
 The canonical git repository is located at https://github.com/codehaus-plexus/plexus-compiler
+
+
+#### Error Prone usage 
+
+Please refer to [documentation](https://errorprone.info/docs/installation#maven)