fix: upgrade imgutil to fix containerd snapshotter issue (#2493)

Upgrades imgutil from v0.0.0-20250814164739-4b1c8875ba7e to
v0.0.0-20250909162057-9db16db815e3 to fix an issue where builder
images created with Docker's containerd snapshotter storage driver
had malformed manifests.

The bug caused the first several base image layers to be replaced
with empty blob references in the manifest, while the config
retained correct diff_ids. This created invalid images that failed
OCI spec validation with tools like skopeo.

The fix was already merged in buildpacks/imgutil#297, which reverted
the problematic "fast path" optimization commits.

Resolves #2490

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Signed-off-by: Juan Bustamante <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: jjbustamante

go.mod

@@ -5,7 +5,7 @@ require (
 	github.com/Masterminds/semver v1.5.0
 	github.com/Microsoft/go-winio v0.6.2
 	github.com/apex/log v1.9.0
-	github.com/buildpacks/imgutil v0.0.0-20250814164739-4b1c8875ba7e
+	github.com/buildpacks/imgutil v0.0.0-20250909162057-9db16db815e3
 	github.com/buildpacks/lifecycle v0.20.19
 	github.com/chainguard-dev/kaniko v1.25.5
 	github.com/containerd/errdefs v1.0.0

go.sum

@@ -98,8 +98,8 @@ github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/buildpacks/imgutil v0.0.0-20250814164739-4b1c8875ba7e h1:a+vpYYeK7E7+3uGqseiRutzKA7yNNjAOPON9+VOADiw=
-github.com/buildpacks/imgutil v0.0.0-20250814164739-4b1c8875ba7e/go.mod h1:UH4th60x/wM1DdH7+eSgzbp0kgsJMhVgngWzXoF21cs=
+github.com/buildpacks/imgutil v0.0.0-20250909162057-9db16db815e3 h1:tm7oOjDEdtwfKL9ukn0cnCo7bgYNYCe0HFk9rbPAKNQ=
+github.com/buildpacks/imgutil v0.0.0-20250909162057-9db16db815e3/go.mod h1:UH4th60x/wM1DdH7+eSgzbp0kgsJMhVgngWzXoF21cs=
 github.com/buildpacks/lifecycle v0.20.19 h1:RyQe2QO524eiJNUpFNTdQKVgasPRP5Dl7zrqrFeJA6k=
 github.com/buildpacks/lifecycle v0.20.19/go.mod h1:Sp2Gc7hPquJ0BivUJjn1FKMzdNNrIAFP0MjNlkwxNGc=
 github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=