Bump skopeo/stable from v1.15.1 to v1.15.2 in /tests in the docker-te…

…sts group (#6029)

Bump skopeo/stable in /tests in the docker-tests group

Bumps the docker-tests group in /tests with 1 update: [skopeo/stable](https://github.com/containers/image_build).


Updates `skopeo/stable` from v1.15.1 to v1.15.2
- [Commits](https://github.com/containers/image_build/commits)

---
updated-dependencies:
- dependency-name: skopeo/stable
  dependency-type: direct:production
  dependency-group: docker-tests
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/Dockerfile

@@ -3,7 +3,7 @@
 FROM kindest/node:v1.30.2@sha256:ecfe5841b9bee4fe9690f49c118c33629fa345e3350a0c67a5a34482a99d6bba
 
 # this is here so we can grab the latest version of skopeo and have dependabot keep it up to date
-FROM quay.io/skopeo/stable:v1.15.1
+FROM quay.io/skopeo/stable:v1.15.2
 
 FROM python:3.12@sha256:b6f142bd70d2219c98c143094ad2a0b8cc882294a7fb2664377a7b68edfc5767