Panel docs, FontAwesome 5 icon classes updates

As FontAwesome 5 site states, fa-code-branch icon replaces Font Awesome 4's fa-code-fork.
Just updated two lines, where old class wasn't replaced.

docs/documentation/components/panel.html

@@ -60,13 +60,13 @@ meta:
   </a>
   <a class="panel-block">
     <span class="panel-icon">
-      <i class="fas fa-code-fork" aria-hidden="true"></i>
+      <i class="fas fa-code-branch" aria-hidden="true"></i>
     </span>
     daniellowtw/infboard
   </a>
   <a class="panel-block">
     <span class="panel-icon">
-      <i class="fas fa-code-fork" aria-hidden="true"></i>
+      <i class="fas fa-code-branch" aria-hidden="true"></i>
     </span>
     mojs
   </a>