Automate kubeVersion bump in Chart.template.yaml alongside Kind version updates

Is your feature request related to a problem? Please describe. The kubeVersion field in deploy/charts/cert-manager/Chart.template.yaml is a static, floor-only semver constraint (>= 1.22.0-0), introduced by #4307 in response to #4132. However, #4132 also asked that this value track the "Supported Releases" page and be kept up to date over time — that part was never implemented, and the issue was auto-closed by the stale bot without further discussion. As a result, the field has not been revisited since, and does not reflect the Kubernetes versions currently listed as supported, nor the Kind node image versions actually exercised in CI. Third-party listings such as Artifact Hub surface this stale value, and a git blame on that line points to a very old commit, giving the impression that Kubernetes compatibility hasn't been reviewed in years.

Describe the solution you'd like cert-manager already ships a make-based automated script (introduced around v1.7, per the release notes) that bumps the Kind node image version used for development/testing. I'd like to see that same automation extended (or a sibling target added) to also update the kubeVersion field in Chart.template.yaml whenever the tested Kind/Kubernetes version changes, so the Helm chart's declared compatibility stays in sync with:

• the Kubernetes versions actually tested via Kind in CI, and
• the versions published on the "Supported Releases" page.

This would close the loop left open by #4132/#4307 and keep a single source of truth instead of relying on someone remembering to bump it by hand.

Describe alternatives you've considered

• Manually bumping kubeVersion on every release — this is presumably what was expected after #4307, and its absence is exactly why the field went stale.
• Fixing only the documentation (Supported Releases page) — doesn't help Helm's own client-side validation or what's surfaced on Artifact Hub, since Helm reads kubeVersion from the chart itself.
• A lighter-weight CI lint step that fails if kubeVersion diverges too far from the Kind version used in tests, as a lower-effort alternative to full automation.

Additional context

• Original ask: #4132 (2021), closed by stale-bot without resolution of the "keep it updated" part.
• Field was introduced by: #4307.
• Example of the resulting drift: https://github.com/cert-manager/cert-manager/blame/613352e67312616846373dc03163c10e9d4ebc5c/deploy/charts/cert-manager/Chart.yaml#L22
• Artifact Hub listing showing the same stale value: https://artifacthub.io/packages/helm/cert-manager/cert-manager

Environment details (remove if not applicable):

• Kubernetes version: N/A (metadata/process issue, not version-specific)
• Cloud-provider/provisioner: N/A
• cert-manager version: N/A
• Install method: Helm

/kind feature