chore(deps): bump sigs.k8s.io/structured-merge-diff/v6 (#924)

Bumps the kubernetes group with 1 update: [sigs.k8s.io/structured-merge-diff/v6](https://github.com/kubernetes-sigs/structured-merge-diff).


Updates `sigs.k8s.io/structured-merge-diff/v6` from 6.4.0 to 6.4.2
- [Release notes](https://github.com/kubernetes-sigs/structured-merge-diff/releases)
- [Changelog](https://github.com/kubernetes-sigs/structured-merge-diff/blob/master/RELEASE.md)
- [Commits](https://github.com/kubernetes-sigs/structured-merge-diff/compare/v6.4.0...v6.4.2)

---
updated-dependencies:
- dependency-name: sigs.k8s.io/structured-merge-diff/v6
  dependency-version: 6.4.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kubernetes
...

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