[ANNOUNCE] KUTTL v0.21.0 is released

[Marcin Owsiany]

🚀 Highlights

• [KEP-0009] feat: add expression based assertions (#576)
  See assertAll and assertAny fields in TestAssert (docs).

🌱 Dependency bumps

• chore(deps): bump the kubernetes group across 1 directory with 7 updates (#604)
• chore(deps): bump github.com/docker/docker from 27.3.1+incompatible to 27.5.1+incompatible (#594, #598, #603)
• chore(deps): bump sigs.k8s.io/controller-runtime from 0.19.2 to 0.19.4 in the kubernetes group (#592, #600)
• chore(deps): bump sigs.k8s.io/controller-tools from 0.16.5 to 0.17.0 in the kubernetes group (#599)
• Bump sigs.k8s.io/kind from 0.25.0 to 0.26.0 in the kubernetes group across 1 directory (#597)
• Bump go, k8s deps and linter versions, and some fixes (#596)

🔧 Other Changes

• chore: explicitly add quotes to error format (#605)
• refactor: moves kubernetes utilities to pkg/kubernetes (#590)
• fix: make sure goreleaser config matches current schema (#588)

Contributors

@dependabot, @dependabot[bot], @kumar-mallikarjuna and @porridge