fix: add typing-extensions to dependencies (#227)

* fix: add  to dependencies

* Handle typing-extensions import based on Python version

* Set typing-extensions min version to 4.0.0

pyproject.toml

@@ -11,6 +11,7 @@ classifiers = [
 ]
 dependencies = [
     "pyarrow>=8.0.0",
+    "typing-extensions>=4.0.0; python_version<'3.10'",
 ]
 
 [project.optional-dependencies]

python/fastexcel/__init__.py

@@ -1,8 +1,12 @@
 from __future__ import annotations
 
+import sys
 from typing import TYPE_CHECKING, Literal
 
-from typing_extensions import TypeAlias
+if sys.version_info < (3, 10):
+    from typing_extensions import TypeAlias
+else:
+    from typing import TypeAlias
 
 if TYPE_CHECKING:
     import pandas as pd