Asdf-coordinates-schemas

------------------

-

------------------

- Add ``asdf-astropy`` as a test dependency. [34]
- Drop official support for Python 3.8 [42]
- Update schemas for ASDF standard 1.6.0 [55]

------------------

- Add documentation to package. [8]
- Update asdf version and require python 3.8. [14]
- Switch to pyproject.toml. [15]

------------------

- Initial release.