Update README.md

Author: jimmyn

README.md

@@ -20,7 +20,7 @@ const mqttClient = new AWSMqtt({
 secretAccessKey: AWS_SECRET_ACCESS_KEY,
 sessionToken: AWS_SESSION_TOKEN,
 endpointAddress: AWS_IOT_ENDPOINT_HOST,
- region: 'us-east-1'
+region: 'us-east-1'
 });
 ````
 4. Connect and recieve messages from your topic