Deprecate pkg_resources

[yihming]

This PR is to fix the deprecation issue on pkg_resources package:

UserWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html. 
The pkg_resources package is slated for removal as early as 2025-11-30. 
Refrain from using this package or pin to Setuptools<81.
  import pkg_resources

Solution: Replace it by importlib.resources which requires Python 3.10+.