Bump K3s version for v1.28

[brandond]

Proposed Changes

Updates k3s: k3s-io/k3s@7d38b4a...9597ea1

Types of Changes

enhancement, bugfix

Verification

See linked issue

Testing

Linked Issues

• [BUG] rke2-etcd-snapshots configmap grows too large when snapshot retention is high #4495
• https://github.com/k3s-io/k3s/blob/master/docs/adrs/etcd-snapshot-cr.md

User-Facing Change

RKE2 now tracks snapshots using custom resource definitions. This resolves an issue where the configmap previously used to track snapshot metadata could grow excessively large and fail to update when new snapshots were taken.

Further Comments

[VestigeJ]

kooo