Dependency on pkg_resources is not declared

[tari]

Since Python 3.12, pkg_resources is not shipped by default with Python. It remains available as a part of the setuptools package, but that should be declared as a dependency to ensure it's available.

importlib.metadata is the intended replacement for the uses of pkg_resources in this package (just getting the package version), but is only available since Python 3.8. Since this package currently supports down to Python 3.7, importlib_metadata can be used instead; that provides a backport of the standard library.

[tari]

#210 provides an alternative to #209 (or interim solution) by declaring a dependency on setuptools.