implement header-2 CTA

_includes/block-header-2.html

@@ -12,7 +12,7 @@
         <li class="nav-item {% if page.url == nav_item.link %}active{% endif %}"><a href="{{ nav_item.link }}">{{ nav_item.link_text }}</a></li>
         {% endfor %}
     </ul>
-    <button class="button primary small block-header-2--cta">Download</button>
+    <a class="button primary small block-header-2--cta" href="{{ section.cta.url }}">{{ section.cta.button_text }}</a>
   </nav>
 
 </header>