deps(docker): bump mvdan/shfmt from v3.8.0 to v3.9.0 (#6052)

Bumps mvdan/shfmt from v3.8.0 to v3.9.0.

---
updated-dependencies:
- dependency-name: mvdan/shfmt
  dependency-type: direct:production
...

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

Dockerfile

@@ -21,7 +21,7 @@ FROM registry.k8s.io/kustomize/kustomize:v5.4.3 AS kustomize
 FROM hashicorp/terraform:1.9.4 AS terraform
 FROM koalaman/shellcheck:v0.10.0 AS shellcheck
 FROM mstruebing/editorconfig-checker:v3.0.3 AS editorconfig-checker
-FROM mvdan/shfmt:v3.8.0 AS shfmt
+FROM mvdan/shfmt:v3.9.0 AS shfmt
 FROM rhysd/actionlint:1.7.1 AS actionlint
 FROM scalameta/scalafmt:v3.8.3 AS scalafmt
 FROM zricethezav/gitleaks:v8.18.4 AS gitleaks