Add support for league/flysystem v2.

[mikeyudin]

Hello,

In league/flysystem-aws-s3-v3, the AwsS3Adaptor class has been renamed to AWSS3V3Adaptor. When trying to upgrade to the newer version of flysystem (in order to work with other updated dependencies), ~v2.0 of flysystem is required.

Are there plans to upgrade this library to support v2? Would you prefer a PR?

Thank you.

[alexandre-mace]

Hello, i think i might have encountered the same issue, i just tried to install vich/uploader-bundle but vich requires flysystem v2 and this package locks me to v1.

Thank you

[danplaton4]

Any updates on this, or package is deprecated?