feat: GET /repos/{owner}/{repo}/readme/{dir} (#68)

BREAKING CHANGE: `operations["packages/get-all-package-versions-for-a-package-owned-by-an-org"]` is now `operations["packages/get-all-package-versions-for-package-owned-by-org"];`

BREAKING CHANGE: `operations["packages/get-all-package-versions-for-a-package-owned-by-the-authenticated-user"]` is now `operations["packages/get-all-package-versions-for-package-owned-by-authenticated-user"];`

Author: octokitbot