fix: adapt to appsync client v3

[5d]

Issue #, if available:

Description of changes:

• adapting dependency appsync client v3 APIs

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[5d]

Sure, I will do the integration test and change it to a fix commit.

[5d]

Verified all integration test cases are passed.

[5d]

closing this PR as https://github.com/awslabs/aws-mobile-appsync-sdk-ios/pull/561 has the similar changes and merged