fixed java se badge

Author: toKrause

README.MD

@@ -2,7 +2,7 @@
 
 [![Build Status](https://travis-ci.org/markenwerk/java-utils-mail-dkim.svg?branch=master)](https://travis-ci.org/markenwerk/java-utils-mail-dkim)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/net.markenwerk/utils-mail-dkim/badge.svg)](https://maven-badges.herokuapp.com/maven-central/net.markenwerk/utils-mail-dkim)
-[![Java SE 6](https://img.shields.io/badge/java-SE_6-brightgreen.svg)](http://docs.oracle.com/javase/6/docs/api/)
+[![Java SE 7](https://img.shields.io/badge/java-SE_7-brightgreen.svg)](http://docs.oracle.com/javase/7/docs/api/)
 [![Apache 2.0 License](https://img.shields.io/badge/license-Apache_2.0-brightgreen.svg)](https://github.com/markenwerk/java-utils-mail-dkim/blob/master/LICENSE)
 
 This is a simple to use library to use [DKIM](https://en.wikipedia.org/wiki/DKIM) features in conjunction with [JavaMail](https://javaee.github.io/javamail/).
@@ -145,4 +145,4 @@ domainKey.check(from, getDkimPrivateKeyFileForSender(from));
 [MimeMessage]: http://javamail.java.net/nonav/docs/api/index.html?javax/mail/internet/MimeMessage.html
 [Session]: http://javamail.java.net/nonav/docs/api/index.html?javax/mail/Session.html
 
-[RSAPrivateKey]: http://docs.oracle.com/javase/8/docs/api/index.html?java/security/interfaces/RSAPrivateKey.html
+[RSAPrivateKey]: http://docs.oracle.com/javase/8/docs/api/index.html?java/security/interfaces/RSAPrivateKey.html