🔖 Bump to 2.5.0

🔖 Bump to v2.4.2

🔖 Bumped to v2.4.0

Bumped Elixir version minimum requirements

Fixed small bug in spec

Fixed Env.type spec

Feat/improve travis ci (#12)

* Added coveralls, format, credo and dialyzer to travis yml build config.

* Added coveralls badge to README

Change default type to any() (#8)

* Change default type to any()

* Updated documentation with current default type

Feature/selective variable binding (#7)

* Added Skogsra.Binding behaviour

* Added selective variable binding

Fix/custom type fails when used (#5)

* Fixed bug where Skogsra.Type couldn't be used

* Added tests for Skogsra.Type use in app_env