ci: allow merging chart changes without a version bump

[secana]

A pull request should be mergeable without bumping the chart version. The change then simply is not released, and ships with the next bump. Requiring a bump per pull request forces a chart release for every merge.

ct lint no longer requires a bump

check-version-increment defaults to true, which is what fails #93 today:

Checking chart "kellnr" for a version bump...
Old chart version: 6.1.7
New chart version: 6.1.7
✖︎ chart version not ok. Needs a version bump!

Disabled in .github/ct.yaml. Everything else ct lint does (helm lint, yamllint, Chart.yaml validation, schema checks) is unaffected.

chart-releaser skips the already released version

This half is needed to keep the first half from just moving the failure to main. chart-releaser-action selects charts by diffing the latest tag against HEAD, not by comparing versions, so a merge that touches charts/ without a bump still counts as changed: it repackages 6.1.7 and tries to upload it, and the release kellnr-6.1.7 already exists. Without skip_existing that aborts the release job.

With skip_existing: true the upload is skipped, the published release is left untouched, and nothing new is created.

Verification

Ran ct 3.14.0 locally, the same version the CI job uses:

• With the new config: Version increment checking disabled. then All charts linted successfully.
• Reconstructed the merge result of feat(kellnr): configure additional OAuth2 audiences #93 on top of this change (its chart edits plus main's Chart.yaml, which feat(kellnr): configure additional OAuth2 audiences #93 does not touch) and ct lint passes. So this unblocks feat(kellnr): configure additional OAuth2 audiences #93 without a bump.

Both changed YAML files parse.

Note

Releases now need a deliberate bump. Nothing prompts for one any more, so chart changes merged without a bump stay unreleased until the next repository_dispatch from a kellnr release bumps the patch and ships everything accumulated since.