v1.6.0

Bump version to 1.6.0

* introduce cargo features
* rename regret to skip-best method
* implement k-regret insertion method
* add recreate-with-perturbation method
* fix issues in init readers
* add local search

v1.5.8

Bump version to 1.5.8

* add area priority
* add support to generate problems in hre format

v1.5.7

Bump version to 1.5.7

* minor improvements

v1.5.6

Bump version to 1.5.6

* testing ci/cd pipeline