aws-appsync-auth-link: replace aws-sdk dependency with @aws-sdk alternatives

[ryanwalters]

Issue #, if available: #577

Description of changes: Remove the aws-sdk dependency by using @aws-sdk/* alternatives.

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[yaquawa]

Thanks man!!! Hi aws team, when will this pr be merged?? I also have a trouble with the old aws-sdk that depends on the very old version of buffer which brokens my whole bundling process.. I really need this PR be merged..!!! Thanks!

[andrejunges]

any updates?

[adamdottv]

This seems like an obvious improvement; any movement here?

[yaquawa]

Hi @ryanwalters, could you publish this as another package(aws-mobile-appsync-sdk-js-v2 for example)? So we can move things forward.. I'm sure this repo is dead.

[ebisbe]

that seems interesting. Not the fact it gets ignored

[alansikora]

Please, approve this...