My plan is to use semver library to achieve so.

The idea is to change

This will allow complex comparisons such as

required_version = ">=1.2.3, <1.8.0"

instead of only plain files.

I'm willing to work on it, btw.

Opening it as an effort to contribute to turning required_version into a stable flag.

### Tasks
- [x] Add tests for current implementation
- [x] Implement new version with `semver`, making sure it does not break old (current) behavior
- [x] Add "stress test" checking multiple definitions to the value (using fancy operators such as `>`, `>=`, `<`, `<=`, `^`, `8`, `~`, etc.), and ensuring it'll work