fix: replace table license with SPDX in pyproject.toml (nhairs#49)

Author: V1rg1lee

pyproject.toml

@@ -22,11 +22,11 @@ dependencies = [
 
 # Extra information
 readme = "README.md"
-license = {text = "BSD-2-Clause License"}
+license = "BSD-2-Clause"
+license-files = ["LICENSE"]
 classifiers = [
     "Development Status :: 6 - Mature",
     "Intended Audience :: Developers",
-    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.8",