Use SPDX license expression in project metadata

Author: Natuworkguy

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["setuptools>=69", "wheel"]
+requires = ["setuptools>=77", "wheel"]
 build-backend = "setuptools.build_meta"
 
 [project]
@@ -8,7 +8,8 @@ dynamic = ["version", "dependencies", "optional-dependencies"]
 description = "2D Game engine made by Natuworkguy for public use."
 readme = "README.md"
 requires-python = ">=3.11"
-license = { text = "GPL-3.0-only" }
+license = "GPL-3.0-only"
+license-files = ["LICENSE"]
 authors = [
   { name = "Nathan C." }
 ]