Add implementation of s3-deploy's "--file-prefix"

[Offlein]

This implements the missing s3-deploy --file-prefix flag, per request in #99 and #21.

Worth noting, however: The --delete-removed flag being true seems to just delete everything that you just uploaded for some reason. I do not know why. I guess you need to give it a glob pattern somehow, but I don't think I really need it so I didn't do more testing.

[Offlein]

Oh, also relevant: it looks to me like s3-deploy is... dead and gone? Maybe? Their homepage was https://github.com/import-io/s3-deploy and that doesn't exist anymore.

Does that pose a problem for this action? And would you ever consider moving it to the aws command-line SDK?

[coliff]

Oh, also relevant: it looks to me like s3-deploy is... dead and gone? Maybe? Their homepage was import-io/s3-deploy and that doesn't exist anymore.

Does that pose a problem for this action? And would you ever consider moving it to the aws command-line SDK?

Yep, we're aware that import-io/s3-deploy is gone and the npm package not being updated. I think at some point this GitHub Action will need to change to continue working as the one being used now relies on a deprecated version of the AWS JS SDK.