Worker volume retention policy

[BrandonCate]

Hello again 👋

This PR adds in the ability to use the persistentVolumeClaimRetentionPolicy feature of statefulsets enabled by default in kubernetes 1.32.
Ref: https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/#persistentvolumeclaim-retention

Why do we need this PR?

With the HPA autoscaling feature this is a nice quality of life to allow developers to choose how they want their PVs to be reclaimed.

Changes proposed in this pull request

persistentVolumeClaimRetentionPolicy feature for worker statefulset and supporting documentation

Contributor Checklist

• Variables are documented in the README.md yes
• Which branch are you merging into? dev
  • master is for changes related to the current release of the concourse/concourse:latest image and should be good to publish immediately
  • dev is for changes related to the next release of Concourse (aka unpublished code on master in concourse/concourse)

Reviewer Checklist

This section is intended for the core maintainers only, to track review progress. Please do not
fill out this section.

• Code reviewed
• Topgun tests run
• Back-port if needed
• Is the correct branch targeted? (master or dev)

[taylorsilva]

Thanks for the PR! I'm running it against our topgun test suite and then I'll merge.

In the future, for these kinds of changes that are updating chart functionality, you can merge them into master, not dev. dev is for when we've done something like added a new CLI flag to the concourse binary. If its a pure chart-feature, like your two PR's have been, you can merge right into master.

For now, don't worry about changing it. I'll get your PR's landing in master in the next chart release.

[BrandonCate]

understood, thank you!