Fix for CVE-2021-40829 in aws/aws-iot-device-sdk-java-v2 (project awslabs__aws-iot-device-sdk-java-v2_CVE-2021-40829_1.4.1), commit v1.4.2
Fixed file: sdk/src/main/java/software/amazon/awssdk/iot/AwsIotMqttConnectionBuilder.java
Fixed class: AwsIotMqttConnectionBuilder (lines 37-432)
Fixed method: withUsername (lines 281-283)
Method signature: AwsIotMqttConnectionBuilder withUsername(String)