refactor: replace pkg_resources with importlib for version handling

Replaced pkg_resources with importlib.metadata to retrieve the
package version. This reduces reliance on setuptools and uses a
standard library available in Python 3.8+.

pyradios/radios.py

@@ -1,12 +1,12 @@
+from importlib.metadata import version as get_version
+
 import httpx
 
 from pyradios.base_url import pick_base_url
 from pyradios.utils import type_check
 
-import pkg_resources
-
 
-version = pkg_resources.get_distribution('pyradios').version
+version = get_version("pyradios")
 
 
 class Request: