message: Add release badge
diff: <a href="https://ci.appveyor.com/project/Romain/lief/branch/master">
  <img src="https://ci.appveyor.com/api/projects/status/0ijlcujac5vh8cas/branch/master?svg=true">
  </a>
  + &nbsp;
  + <a href="https://github.com/lief-project/LIEF/releases">
  + <img src="https://img.shields.io/badge/release-0.6.0-brightgreen.svg?style=default">
  + </a>
  </p>
  @@ -113,7 +117,8 @@ int main(int argc, const char** argv) {
  Romain Thomas - [Quarkslab](https://www.quarkslab.com)
  -<hr />
  +---------------
  +
  <p align="center" >
  <img width="40%" src="http://lief.quarkslab.com/resources/QB-big.png"/>
  </p>
  