(torchx/entrypoints) Use importlib.metadata instead of the backported importlib_metadata

Summary: torchx dropped support for python<=3.7 2 years ago (see: #728). But we kept using the backported `importlib_metadata` module to load configurations from `entry_points`.

Differential Revision: D77619564

Author: kiukchung

requirements.txt

@@ -1,6 +1,5 @@
 pyre-extensions
 docstring-parser>=0.8.1
-importlib-metadata
 pyyaml
 docker
 filelock

torchx/util/entrypoints.py

@@ -6,11 +6,10 @@
 
 # pyre-strict
 
+from importlib import metadata
+from importlib.metadata import EntryPoint
 from typing import Any, Dict, Optional
 
-import importlib_metadata as metadata
-from importlib_metadata import EntryPoint
-
 
 # pyre-ignore-all-errors[3, 2]
 def load(group: str, name: str, default=None):

torchx/util/test/entrypoints_test.py

@@ -8,12 +8,12 @@
 
 import unittest
 from configparser import ConfigParser
+
+from importlib.metadata import EntryPoint, EntryPoints
 from types import ModuleType
 from typing import List
 from unittest.mock import MagicMock, patch
 
-from importlib_metadata import EntryPoint, EntryPoints
-
 from torchx.util.entrypoints import load, load_group