Update version number to 6.4.1 #76

Job	Run time
Azure_IoT_Windows	2m 23s
Azure_IoT / run_tests	4m 50s
Crypto / run_tests	4m 49s
MQTT / run_tests	4m 46s
MQTT_Interoperability / run_tests	7m 16s
NetXDuo / run_tests	54m 43s
NetXDuo_Fast / run_tests	5m 30s
NetXDuo64 / run_tests	3m 17s
PTP / run_tests	3m 31s
Secure / run_tests	16m 47s
Secure_Interoperability / run_tests	42m 25s
Web / run_tests	2m 23s
Web / deploy_code_coverage	0s
NetXDuo64 / deploy_code_coverage	0s
PTP / deploy_code_coverage	0s
MQTT / deploy_code_coverage	0s
Crypto / deploy_code_coverage	0s
Azure_IoT / deploy_code_coverage	0s
NetXDuo_Fast / deploy_code_coverage	0s
MQTT_Interoperability / deploy_code_coverage	0s
Secure / deploy_code_coverage	0s
Secure_Interoperability / deploy_code_coverage	0s
NetXDuo / deploy_code_coverage	0s
Deploy / run_tests	0s
Deploy / deploy_code_coverage	0s
	2h 32m 40s

Provide feedback