Use with AsyncAWS instead of AwsSDK

[benr77]

Hello.
Is it possible to use this package with AsyncAWS instead of the full bloated AwsSdk.

So AsyncAws\Flysystem\S3\AsyncAwsS3Adapter instead of League\Flysystem\AwsS3v3\AwsS3Adapter

Thanks

[Nyholm]

Hey.

Yeah. That would be great. I made a PR here with that support: backup-manager/backup-manager#168