added README

Author: hboutemy

README.md

@@ -0,0 +1,6 @@
+Plexus Parent POM
+============
+
+[![Maven Central](https://img.shields.io/maven-central/v/org.codehaus.plexus/plexus.svg?label=Maven%20Central)](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22org.codehaus.plexus%22%20a%3A%plexus%22)
+
+The current master is now at https://github.com/codehaus-plexus/plexus-pom