v0.19.0

Starting with this release, Butane binaries are signed with the Fedora 38
key.

Breaking changes

• Spec implementations require a FieldFilters() method (Go API)
• Reports from Unvalidated functions can now include json paths (Go API)

Features

• Add -c/--check option to check config without producing output
• Warn if config attempts to reuse partition by label (fcos 1.6.0-exp,
  openshift 4.14.0)
• Require storage.filesystems.path to start with /etc or /var if
  with_mount_unit is true (fcos 1.6.0-exp, openshift 4.14.0)
• Stabilize OpenShift spec 4.14.0, targeting Ignition spec 3.4.0
• Add OpenShift spec 4.15.0-experimental, targeting Ignition spec
  3.5.0-experimental

Bug fixes

• Fix line/column reporting for http_headers errors
• Fix line/column reporting for unsupported field errors (r4e)

Misc. changes

• Add error structs for YAML unmarshal errors, unknown config versions (Go API)
• Roll back to Ignition spec 3.4.0 (openshift 4.14.0)

Docs changes

• Document consequence of setting systemd.units.mask to false
• Document grub section (openshift 4.15.0-exp)
• Document /dev/disk/by-id/coreos-boot-disk (fcos, openshift 4.11.0+)
• Don't claim to support generating swap units (openshift 4.8.0 - 4.13.0)
• Document key_file compression field (openshift 4.8.0 - 4.9.0)
• Document support for special mode bits and arn URLs (r4e 1.1.0+)
• Improve rendering of spec docs on docs site