Fix Gravatar support (#865)

Thank you @sardaukar!

src/www/index.html

@@ -502,7 +502,7 @@
   <script src="./js/vendor/vue-i18n.min.js"></script>
   <script src="./js/vendor/apexcharts.min.js"></script>
   <script src="./js/vendor/vue-apexcharts.min.js"></script>
-  <script src="./js/vendor/sha512.min.js"></script>
+  <script src="./js/vendor/sha256.min.js"></script>
   <script src="./js/vendor/timeago.full.min.js"></script>
   <script src="./js/api.js"></script>
   <script src="./js/i18n.js"></script>

src/www/js/app.js

@@ -138,7 +138,7 @@ new Vue({
       const clients = await this.api.getClients();
       this.clients = clients.map((client) => {
         if (client.name.includes('@') && client.name.includes('.')) {
-          client.avatar = `https://www.gravatar.com/avatar/${sha512(client.name)}?d=blank`;
+          client.avatar = `https://gravatar.com/avatar/${sha256(client.name.toLowerCase().trim())}.jpg`;
         }
 
         if (!this.clientsPersist[client.id]) {