Update ecosystem sort dropdown menu (#54)

Author: patmellon

_includes/ecosystem_sort.html

@@ -12,15 +12,23 @@
       <li>
         <a class="ecosystem-filter" id="sortHighLeft">GitHub Stars - Highest</a>
       </li>
+    </ul>
+
+    <hr>
 
+    <ul>
       <li>
         <a class="ecosystem-filter" id="sortDateNew">Date Added - Newest</a>
       </li>
 
       <li>
         <a class="ecosystem-filter" id="sortDateOld">Date Added - Oldest</a>
       </li>
+    </ul>
+
+    <hr>
 
+    <ul>
       <li>
         <a class="ecosystem-filter" id="sortTitleHigh">Title - A-Z</a>
       </li>