v0.18.0

Breaking changes

• Remove deprecated rhcos variant

Features

• Support offline Tang provisioning via pre-shared advertisement (fcos 1.5.0+,
  openshift 4.14.0-exp)
• Support local file embedding for SSH keys and systemd units (fcos 1.5.0+,
  flatcar 1.1.0+, openshift 4.14.0-exp, r4e 1.1.0+)
• Allow enabling discard passthrough on LUKS devices (fcos 1.5.0+,
  flatcar 1.1.0+, openshift 4.14.0-exp)
• Allow specifying arbitrary LUKS open options (fcos 1.5.0+,
  flatcar 1.1.0+, openshift 4.14.0-exp)
• Allow specifying user password hash (openshift 4.13.0+)
• Stabilize Fedora CoreOS spec 1.5.0, targeting Ignition spec 3.4.0
• Stabilize Flatcar spec 1.1.0, targeting Ignition spec 3.4.0
• Stabilize OpenShift spec 4.13.0, targeting Ignition spec 3.2.0
• Stabilize RHEL for Edge spec 1.1.0, targeting Ignition spec 3.4.0
• Add Fedora CoreOS spec 1.6.0-experimental, targeting Ignition spec
  3.5.0-experimental
• Add Flatcar spec 1.2.0-experimental, targeting Ignition spec
  3.5.0-experimental
• Add OpenShift spec 4.14.0-experimental, targeting Ignition spec
  3.5.0-experimental
• Add RHEL for Edge spec 1.2.0-experimental, targeting Ignition spec
  3.5.0-experimental

Bug fixes

• Use systemd default dependencies in mount units for Tang-backed LUKS volumes
• Allow setting storage.trees.local to the --files-dir directory

Misc. changes

• Roll back to Ignition spec 3.2.0 (openshift 4.13.0)
• Drop extensions section (fcos 1.5.0+, openshift 4.13.0+)
• Drop LuksOption and RaidOption types (Go API for fcos 1.5.0+,
  flatcar 1.1.0+, openshift 4.14.0-experimental)
• Require Go 1.18+

Docs changes

• Document that hash fields describe decompressed data
• Clarify spec docs for files/luks hash fields
• Document SSH key file path used by OpenShift 4.13+ (openshift)
• Document command to generate GRUB password hashes