packwerk-extensions is a home for checker extensions for packwerk 3.

Currently, it ships the following checkers to help improve the boundaries
between packages. These checkers are:
- A privacy checker that ensures other packages are using your package's public
  API
- A visibility checker that allows packages to be private except to an explicit
  group of other packages.
- A folder_privacy checker that allows packages to their sibling packs and
  parent pack (to be used in an application that uses folder packs)
- A layer (formerly architecture) checker that allows packages to specify their
  "layer" and requires that each layer only communicate with layers below it.