Squashed commit of the following

commit 04e49a0d 
Author: zhijie wang <wanzhiji@amazon.com> 
Date: Mon Dec 28 2020 19:10:30 GMT-0800 (Pacific Standard Time) 

    fix Cognito region services


commit fca15a32 
Author: zhijie wang <wanzhiji@amazon.com> 
Date: Mon Dec 28 2020 13:56:14 GMT-0800 (Pacific Standard Time) 

commit eaf5dcc4 
Author: zhijie wang <wanzhiji@amazon.com> 
Date: Mon Dec 28 2020 13:35:25 GMT-0800 (Pacific Standard Time) 

    fix cognito client


commit 9ceee335 
Author: zhijie wang <wanzhiji@amazon.com> 
Date: Mon Dec 28 2020 13:20:15 GMT-0800 (Pacific Standard Time) 

    bump core service version


commit 30d44fe4 
Author: zhijie wang <wanzhiji@amazon.com> 
Date: Mon Dec 21 2020 15:03:10 GMT-0800 (Pacific Standard Time) 

    fix pom version