Hi 👋

This is something of a duplicate / reopen of #1075

I'd also really like to have the expiry window for the AWS IAM window be customizable.

We (at https://github.com/secureCodeBox/secureCodeBox) use the minio client to create presigned url for objects in the s3 buckets.
People using the AWS IAM authentication method often run into problems when the token lifetime is coming to the end and a presigned url is created that has a longer lifetime than the token. AWS then seems to cap the lifecycle of the presigned url to the lifetime of the token (which makes sense)

So for us it would be ideal if we had some way to configure it from the default of 15min, say 1h or 4h so that the presigned urls have a longer min. lifetime than the 15min.

If thats cool with you'all I'm happy to try to open up a PR for it.