Replacing the deprecated pkg_resources import with importlib.metadata

[malteos]

The pkg_resources package is deprecated. See https://setuptools.pypa.io/en/latest/pkg_resources.html

This PR replaces the pkg_resources import with importlib.metadata as suggested in the official docs:

Use of pkg_resources is deprecated in favor of importlib.resources, importlib.metadata and their backports (importlib_resources, importlib_metadata).