Updated sample to use gmp-marker-3d

Author: oppenheimera

samples/3d-marker-html/index.html

@@ -20,7 +20,7 @@
             tilt="65"
             range="800"
             mode="SATELLITE">
-            <gmp-marker position="40.7489,-73.9680" title="UN Headquarters">
+            <gmp-marker-3d position="40.7489,-73.9680" title="UN Headquarters">
                 <div class="custom-marker">
                     United Nations Secretariat Building
                 </div>