update README

README.md

@@ -1,7 +1,9 @@
+**NOTICE:** v9 has entered maintenance status as of 2019-12-24. Please make all new functionality PR's against master.
+
 Package validator
 ================
 <img align="right" src="https://raw.githubusercontent.com/go-playground/validator/v9/logo.png">[![Join the chat at https://gitter.im/go-playground/validator](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/go-playground/validator?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-![Project status](https://img.shields.io/badge/version-9.30.2-green.svg)
+![Project status](https://img.shields.io/badge/version-9.31.0-green.svg)
 [![Build Status](https://semaphoreci.com/api/v1/joeybloggs/validator/branches/v9/badge.svg)](https://semaphoreci.com/joeybloggs/validator)
 [![Coverage Status](https://coveralls.io/repos/go-playground/validator/badge.svg?branch=v9&service=github)](https://coveralls.io/github/go-playground/validator?branch=v9)
 [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/validator)](https://goreportcard.com/report/github.com/go-playground/validator)