♻️ refactor: adopt PEP 639 license metadata (#85)

Co-authored-by: Nyakku Shigure <sigure.qaq@gmail.com>

Author: ShigureNyako

pyproject.toml

@@ -9,9 +9,9 @@ readme = "README.md"
 requires-python = ">=3.10"
 authors = [{ name = "Nyakku Shigure", email = "sigure.qaq@gmail.com" }]
 keywords = ["codespan-reporting"]
-license = { text = "MIT" }
+license = "MIT"
+license-files = ["LICENSE"]
 classifiers = [
-  "License :: OSI Approved :: MIT License",
   "Programming Language :: Rust",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",