v0.3.0

Breaking changes:

• config: Single, unified config file, #284
• config: cwd is a required default and must be absolute, #286,
  #307, #308, #312
• config: Qualify the name of the version field, #309
• config-linux: Convert classID from hex to uint32, #296
• config-linux: Separate mknod from cgroups, #298

Additions:

• config-linux: Add NoNewPrivileges setting for linux, #290

Minor fixes and documentation:

• config-linux: Clarify oom_score_adj, #236, #292
• config-linux: Update links to cgroups documentation, #318
• config-linux: Remove pointers for slices preferring omitempty
  tag instead, #316
• README: add runtime, bundle, and hook author user, #280
• ROADMAP: reshuffled and split into GitHub issues, #300, #301,
  #304, #306
• style: Collect established styles in a discoverable location, #287, #311