horizon-spec-lens-0.1: ChangeLog.md

# Changelog for horizon-spec-lens

## 0.1

* lens classes and instances for `horizon-spec-0.6.*`.
* Add `HasPackageSet` class.
* Add `HasPackages` class.
* Add `HasPackageSet` instances for `Overlay`,
  `PackageSetExportSettings`, `OverlayExportSettings`,
  `HorizonExport`.
* Add `HasPackages` instances for `Overlay`,
  `PackageSetExportSettings`, `OverlayExportSettings`,
  `HorizonExport`.
* Add `Ixed` and `At` instances for `PackageList`, `Overlay`,
  `PackageSetExportSettings`, `OverlayExportSettings`,
  `HorizonExport`.