Absolute paths support

[raulsh]

Hi,

I'm using s3-cache plugin and I need to cache an absolute path (/var/lib/docker), so for doing that compression lib must accept and work with absolute paths. There is a line that trim the first "/", and there is the reason that the plugin can't work with absolute path.

I know that this repo used by multiple cache plugins (not only s3), so there is a reason for trimming the path?

drone-cache-lib/archive/tar/tar.go

Line 63 in 9818686

header.Name = strings.TrimPrefix(filepath.ToSlash(path), "/")