Update default.vue (#170)

Minor Edit
Add your Github project URL as a link 
I find it useful to refer to your github repo for this project!

Author: ellsm

app/layouts/default.vue

@@ -5,7 +5,7 @@
     </v-main>
     <v-footer class="bg-indigo-lighten-1 text-center d-flex flex-column fixed-footer">
       <div class="px-4 py-2 text-center w-100">
-        {{ new Date().getFullYear() }} — <strong>Copilot Metrics Viewer</strong> — {{ version }}
+        {{ new Date().getFullYear() }} — <strong><a href="https://github.com/github-copilot-resources/copilot-metrics-viewer" target="_blank" rel="noopener noreferrer" style="color: inherit;">Copilot Metrics Viewer</a></strong> — {{ version }}
       </div>
     </v-footer>
   </v-app>
@@ -28,4 +28,4 @@ useHead({
   height: 50px;
   max-height: 50px;
 }
-</style>
+</style>