This code was copied from github.com/moby/moby/pkg/archive;
28842d3f09,
which got later simplified in
a5aed699cf
This patch aligns the containerd implementation with those changes, and uses
filepath.ToSlash() unconditionally on all platforms, as it's a no-op on platforms
that use a forward-slash; https://github.com/golang/go/blob/go1.19/src/path/filepath/path.go#L175-L183
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
19db697a5a