fix: replace deprecated pkg_resources with pathlib in benchmark test

pkg_resources is no longer bundled by default in Python 3.12+,
causing ModuleNotFoundError that blocks all test collection.
Replace with pathlib which is stdlib and works on all supported versions.

Author: thpierce

tests/test_local_sampling_benchmark.py

@@ -1,17 +1,16 @@
 import json
 import pkgutil
-from pkg_resources import resource_filename
+from pathlib import Path
 
 # Faster
 def test_pkgutil_static_read(benchmark):
     def get_sampling_rule():
-        # `.decode('utf-8')` needed for Python 3.4, 3.5
         return json.loads(pkgutil.get_data(__name__, 'mock_sampling_rule.json').decode('utf-8'))
     benchmark(get_sampling_rule)
 
 # Slower
-def test_pkg_resources_static_read(benchmark):
+def test_pathlib_static_read(benchmark):
     def get_sampling_rule():
-        with open(resource_filename(__name__, 'mock_sampling_rule.json')) as f:
+        with open(Path(__file__).parent / 'mock_sampling_rule.json') as f:
             return json.load(f)
     benchmark(get_sampling_rule)