✏️ Fix the year in OctoPi-UpToDate's "About"

Author: foosel

octoprint_pi_support/templates/pi_support_about_octopiuptodate.jinja2

@@ -12,7 +12,7 @@
 </ul>
 
 <p>
-    &copy; 2013-{{ now.strftime("%Y") }} <a href="https://github.com/OctoPrint/OctoPi-UpToDate/graphs/contributors" target="_blank" rel="noreferrer noopener">The OctoPi-UpToDate Authors</a>
+    &copy; 2021-{{ now.strftime("%Y") }} <a href="https://github.com/OctoPrint/OctoPi-UpToDate/graphs/contributors" target="_blank" rel="noreferrer noopener">The OctoPi-UpToDate Authors</a>
 </p>
 
 <p>