1.2.0: Require composer ^2.0

Composer ^1.0 is end of life. It makes no sense to still support it. Repositories that need it can still use an older version of this package.

Compatibility with composer 2

Merge pull request #2 from mediact/feature/composer-2-compatibility

Allow both major versions of composer

1.0.1: Merge pull request #1 from mediact/feature/lisence

Add MIT License, use public packages.