Add static timezone suffix (#4912)

* Update default.html

* Update default.html

_layouts/default.html

@@ -84,7 +84,7 @@
       </div>
       <div id="buildNumber" class="desktop-only" title="{{ site.github.build_revision }}">
         Build #: {{ site.github.build_revision | slice: 0,7 }}<br>
-        Build Date: {{ site.time | slice: 0,10}}
+        Build Date: {{ site.time | slice: 0,10}} UTC
       </div>
     </div>