0.04 February 2018
- Fix for https://rt.cpan.org/Public/Bug/Display.html?id=124457 /
  https://github.com/hoehrmann/Graph-Feather/issues/1

0.03 February 2018
- Allow undef as attribute value

0.02 February 2018
- internal: more TODO comments
- internal: use _prepare method throughout
- internal: code simplification with prepared statements
- internal: minor improvements to DB schema
- internal: use sqlite_update_hook instead of triggers
            to support objects as attribute values

0.01 January 2018
- Initial release