fix: Prior to 0.90.0 is_admin doesn't exist check for it to exist and…

… not true

Fixes #207

lib/ha-websocket.js

@@ -77,7 +77,7 @@ class HaWebsocket extends EventEmitter {
 
         // Check if user has admin privileges
         const user = await this.getUser();
-        if (!user.is_admin) {
+        if (user.is_admin === false) {
             this.connectionState = HaWebsocket.ERROR;
             this.client.close();
             throw new Error(