Update to version 0.3.1

Major refacto

## MaxPlus v0.2.0

[Diff since v0.1.0](v0.1.0...v0.2.0)



**Merged pull requests:**
- Install TagBot as a GitHub Action (#2) (@JuliaTagBot)

See github.com/Lecrapouille/MaxPlus.jl/releases/tag/v0.1.0 for releas…

…e notes