update email default year and name

from 2016 grafana and raintank to 2018 Grafana Labs

emails/templates/layouts/default.html

@@ -143,7 +143,7 @@ td[class="stack-column-center"] {
 											<center>
 												<p style="text-align: center; font-size: 12px; color: #999999;">
 													Sent by <a href="[[.AppUrl]]">Grafana v[[.BuildVersion]]</a>
-													<br />&copy; 2016 Grafana and raintank
+													<br />&copy; 2018 Grafana Labs
 												</p>
 											</center>
 										</td>