Get rid of dependency on distutils (#2540)

`distutils` is deprecated and removed from Python 3.12. We don't really
need it since the regex is already producing a well formatted version
number already here. Using `packaging.Version` should be good enough.

Author: pchen7e2

coremltools/optimize/torch/_utils/torch_utils.py

@@ -10,7 +10,7 @@
 import operator as _operator
 import re as _re
 from contextlib import contextmanager
-from distutils.version import StrictVersion as _StrictVersion
+from packaging.version import Version as _Version
 from typing import Any as _Any
 from typing import Dict as _Dict
 from typing import List as _List
@@ -243,7 +243,7 @@ def get_torch_version(version):
     """
     version_regex = r"\d+\.\d+\.\d+"
     version = _re.search(version_regex, str(version)).group(0)
-    return _StrictVersion(version)
+    return _Version(version)
 
 
 def normalize_fsdp_module_name(module_name: str) -> str:

coremltools/optimize/torch/quantization/modules/observers.py

@@ -9,7 +9,7 @@
 # Implementation for EMAMinMaxObserver has been adapted from
 # https://github.com/ModelTC/MQBench/blob/main/mqbench/observer.py
 
-import distutils as _distutils
+from packaging.version import Version as _Version
 from typing import Any as _Any
 from typing import Dict as _Dict
 from typing import Optional as _Optional
@@ -76,7 +76,7 @@ def __init__(
         is_dynamic: bool = False,
     ):
         kwargs = {}
-        if _get_torch_version(_torch.__version__) >= _distutils.version.StrictVersion("2.2"):
+        if _get_torch_version(_torch.__version__) >= _Version("2.2"):
             kwargs["is_dynamic"] = is_dynamic
 
         super(CustomObserverBase, self).__init__(