Gemspec improvements (#109)
Gemspec improvements (#109)

* Specify actual authors of the gem

* Fix and improve gem's `summary` and `description`

* Remove useless `require_paths` and `test_files`

* Improve required Ruby version lock, avoid 3.0

* Add versions locks for dependencies

It's very dangerous and unstable to have dependencies without any version lock,
they may update at any time and without backward compatibility.
codecov/codecov-ruby