2.0.0

Bump PHP version to 8.0+, switch to PSR-11 container interface 2.0

Full Changelog: 1.1.3...2.0.0

Documentation & metadata improvements

• Add keywords and provide to composer.json
• Update README

Add BDD tests

• Rewrite tests to Peridot (http://peridot-php.github.io/)
• Drop PHP 7.0 support grimacing

Bug fix

• Fix a bug in test suite code to detect interrupted test runs

Initial implementation

• PHP 7.0+, PHP 8.0 support
• Tests