Update kube, k8s-openapi and hcloud to their current releases #50

kube, k8s-openapi and hcloud are several releases behind, and each update needs code changes, so they don't fit into a lockfile refresh. I'd like to do them after #37, #47 and #49 are merged, since those touch the same files.

kube 0.96 to 4.2 changes the event Recorder: it takes the object in publish and keeps a cache, which aggregates repeated events into a series (#45). The chart role then needs patch on events. Timestamps move from chrono to jiff, and API errors from ErrorResponse to Status. Controller::reconcile_on is still behind an unstable feature in 4.2. kube 4.2 needs Rust 1.89.

k8s-openapi 0.23 to 0.28 drops the v1_31 feature. The oldest supported API is 1.32, so robotlb would stop supporting clusters older than that.

hcloud 0.21 to 0.26 makes request bodies in the *Params structs required, and Configuration.base_path became a map. No release exposes response headers, so RateLimit-Reset still needs a separate HTTP call.