Request to add a cutoff second setting feature to the S3 input plugin

[yongkyun]

There are cases where the difference between the creation time of a file in S3 and the time it's listed can exceed 20 seconds, resulting in missing processing of files with the same creation time.

To prevent missing files, please add a feature that allows you to set the CUTOFF_SECOND value within the S3 input plugin, rather than fixing it to 3.

Configuration Example
input {
s3 {
....
"cutoff_second" => 60
....
}
}