fix(build): Use SPDX license expression (#310)

Author: cclauss

pyproject.toml

@@ -10,14 +10,14 @@ authors = [
 ]
 description = "A fork of the GYP build system for use in the Node.js projects"
 readme = "README.md"
-license = { file="LICENSE" }
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
 requires-python = ">=3.9"
-dependencies = ["packaging>=24.0", "setuptools>=69.5.1"]
+dependencies = ["packaging>=24.0", "setuptools>=77.0.3"]
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Environment :: Console",
     "Intended Audience :: Developers",
-    "License :: OSI Approved :: BSD License",
     "Natural Language :: English",
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",