Release v0.4.0 created by github-actions[bot] on 10 April 2021, 14:24:36 UTC
[Diff since v0.3.1](https://github.com/javierbarbero/DataEnvelopmentAnalysis.jl/compare/v0.3.1...v0.4.0)
- Add Hölder distance function model. - Add Reverse directional distance function model.
