updated README to better show that this is a deprecated svn location

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1828169 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/README b/README
index 4667c89..f5f8953 100644
--- a/README
+++ b/README
@@ -5,3 +5,6 @@
 
 Users list: users@maven.apache.org
 Developers list: dev@maven.apache.org
+
+Moved to Git in one separate maven-*-plugin.git repository per plugin: don't use this deprecated maven-plugins.git svn mirror
+