Gachinetes ♂ v0.2.0

Added

• CI on pull requests and on main: gofmt, go vet and go test for both
  modules, and every component image built without pushing.
• The tape in S3. gachi-tape ships the tape (a base, then the journal)
  to S3-compatible storage as it is written: one shipper per cluster by
  lease, settings from --replicate flags or the Secret
  gachinetes/gachi-tape-replica, age encryption (unencrypted only on
  request), a new base daily, retention. gachictl tape restore --from s3://… [--at TIME|REVISION] --data-dir DIR brings the store back with its
  history after the cluster is lost. Needs kuberoot-store with
  /tape/v1/journal and tape restore (kuberoot-dev/kuberoot#48).
• Fantasies as preview environments. gachictl fantasy preview --pr URL|N --manifests DIR [--ttl 72h] runs a fantasy of a pull request's
  manifests as a Job in gachi-fantasies, publishes its report and the
  branch's kubeconfig, and keeps it up until the TTL; fantasy merge
  applies the manifests unless the cluster moved on, fantasy discard and
  fantasy list. New image gachi-fantasy-preview (Dockerfile.preview),
  deploy/fantasy-preview.yaml, and a GitHub Actions example in
  examples/github/. gachi-fantasy gains --preview, --ttl, --listen
  and --san.

Changed

• hack/kuberoot.sh builds kuberoot's main by default (fetched first);
  KUBEROOT_REF picks another ref, such as a branch not merged yet.
• CRI-O v1.37.3 (was v1.37.2); CRIU stays at v4.3, the latest release.
• Kubernetes libraries and the stand's binaries v1.37.2 (were v1.37.1).
• README: a table of component versions and where each is set.
• The release workflow, run by hand, pushes the branch's images as :edge
  for trying main between releases.

Known issues

• The between-people phase of the design is not implemented.
• The release images are built from this repository only; the kuberoot base
  images and a gachi-scheduler image are not part of this release (the
  gachi-scheduler binary is in the tarballs).