fix(deps): update dependency skopeo to v1.21.0 (#2728)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

linux/Dockerfile

@@ -52,7 +52,7 @@ RUN install-tool buildx v0.30.1
 RUN install-tool kustomize 5.8.0
 
 # renovate: datasource=github-releases packageName=visualon/skopeo-prebuild
-RUN install-tool skopeo 1.20.0
+RUN install-tool skopeo 1.21.0
 
 # renovate: datasource=java-version packageName=java-jre?os=linux&architecture=x64
 RUN install-tool java 21.0.9+10.0.LTS