Package metadata version retrieval fix.

[guillermodotn]

The package relies on setuptools to retrieve the package metadata version. However, this dependency is not included in pyproject.toml, leading to runtime errors, as described in issue #390.

Following the recommendation in the version.py module, the package will omit pkg_resources.get_distribution and instead utilize the built-in importlib.metadata.version method to retrieve the package version for Python version 3.8 and above.

For older Python versions (< 3.8), setuptools will be installed as a dependency.

[guillermodotn]

Fixes: #390