Require ml_dtypes>=0.5.0 (#188)

Require ml_dtypes>=0.5.0 as a dependency because an older version of it
does not have all the dtypes we need.

---------

Signed-off-by: Justin Chu <justinchuby@users.noreply.github.com>

Author: justinchuby

pyproject.toml

@@ -21,7 +21,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
 ]
-dependencies = ["numpy", "onnx>=1.16", "typing_extensions>=4.10", "ml_dtypes"]
+dependencies = ["numpy", "onnx>=1.16", "typing_extensions>=4.10", "ml_dtypes>=0.5.0"]
 
 [project.urls]
 Homepage = "https://onnx.ai/ir-py"

src/onnx_ir/_enums.py

@@ -422,15 +422,9 @@ def __str__(self) -> str:
     np.dtype(ml_dtypes.float8_e8m0fnu): DataType.FLOAT8E8M0,
     np.dtype(ml_dtypes.int4): DataType.INT4,
     np.dtype(ml_dtypes.uint4): DataType.UINT4,
+    np.dtype(ml_dtypes.float4_e2m1fn): DataType.FLOAT4E2M1,
 }
 
-# TODO(after min req for ml_dtypes>=0.5): Move this inside _NP_TYPE_TO_DATA_TYPE
-_NP_TYPE_TO_DATA_TYPE.update(
-    {np.dtype(ml_dtypes.float4_e2m1fn): DataType.FLOAT4E2M1}
-    if hasattr(ml_dtypes, "float4_e2m1fn")
-    else {}
-)
-
 # ONNX DataType to Numpy dtype.
 _DATA_TYPE_TO_NP_TYPE = {v: k for k, v in _NP_TYPE_TO_DATA_TYPE.items()}