replaced some deprecated var with let

_src/assets/ts/snakeMultiplayer.ts

@@ -246,10 +246,10 @@ setupMQTT();
 
 
 function makeid(length:number) {
-    var result           = '';
-    var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
-    var charactersLength = characters.length;
-    for ( var i = 0; i < length; i++ ) {
+    let result           = '';
+    let characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+    let charactersLength = characters.length;
+    for ( let i = 0; i < length; i++ ) {
         result += characters.charAt(Math.floor(Math.random() * charactersLength));
     }
     return result;