updated readme to correct version

Author: ic0ns

README.md

@@ -1,6 +1,6 @@
 # TLS-Attacker
 
-[![release](https://img.shields.io/badge/Release-v3.3.0-blue.svg)](https://github.com/RUB-NDS/TLS-Attacker/releases)
+[![release](https://img.shields.io/badge/Release-v3.4.0-blue.svg)](https://github.com/RUB-NDS/TLS-Attacker/releases)
 ![licence](https://img.shields.io/badge/License-Apachev2-brightgreen.svg)
 [![travis](https://travis-ci.org/RUB-NDS/TLS-Attacker.svg?branch=master)](https://travis-ci.org/RUB-NDS/TLS-Attacker)