fix link in footer

src/components/footer.js

@@ -25,7 +25,7 @@ class Footer extends Component {
   render() {
     return (
       <footer className="app-footer">
-        Copyright &copy; {new Date().getFullYear()} - <a href="https://acs.eonerc.rwth-aachen.de">Institute for Automation of Complex Power Systems</a> - <a href="https://www.rwth-aachen.de">RWTH Aachen University</a>
+        Copyright &copy; {new Date().getFullYear()} - <a href="https://www.acs.eonerc.rwth-aachen.de">Institute for Automation of Complex Power Systems</a> - <a href="https://www.rwth-aachen.de">RWTH Aachen University</a>
       </footer>
     );
   }