Support python 3.8

Author: ybyygu

Cargo.toml

@@ -47,7 +47,7 @@ adhoc = []
 version = "0.18.1"
 # multiple-pymethods requires Rust 1.62 or above
 # features = ["extension-module", "anyhow", "abi3-py39", "multiple-pymethods"]
-features = ["extension-module", "anyhow", "abi3-py39"]
+features = ["extension-module", "anyhow", "abi3-py38"]
 
 [lib]
 name = "spdkit"

spdkit/__init__.py

@@ -1,4 +1,7 @@
 # [[file:../spdkit-python.note::fbe586a0][fbe586a0]]
+# required for python 3.8
+from __future__ import annotations
+
 from .spdkit import *
 from typing import Dict, List, Sequence, Tuple, Union