Add linkedin social icon link (#26)

Author: lucianomlima

index.html

@@ -260,6 +260,7 @@ <h2>Da Web ao App</h2>
             <a rel="external" target="_blank" href="https://www.youtube.com/c/ReactSalvador"><i class="fab fa-youtube"></i></a>
             <a rel="external" target="_blank" href="https://meetup.com/pt-BR/reactssa/"><i class="fab fa-meetup"></i></a>
             <a rel="external" target="_blank" href="https://github.com/ReactSSA"><i class="fab fa-github"></i></a>
+            <a rel="external" target="_blank" href="https://www.linkedin.com/company/reactssa"><i class="fab fa-linkedin"></i></a>
             <a rel="external" target="_blank" href="https://twitter.com/ReactSSA"><i class="fab fa-twitter-square"></i></a>
             <a rel="external" target="_blank" href="https://facebook.com/reactssa"><i class="fab fa-facebook"></i></a>
         </div>