Release 0.4.0

See #37, release log:

• 9216eec by @rultor: version 0.4.0
• c729bb8 by @rafamizes: style: run Dart format
• 1c35e07 by @rafamizes: test: add more unit tests Clos...
• 91c583a by @rafamizes: style: stricter linting rules ...
• 377f8f0 by @rafamizes: refactor: rename class Rand to...
• 4729b9c by @rafamizes: feat: create RandText class Cl...
• bb35e25 by @rultor: version 0.3.1

Released by Rultor 1.70.6, see build log