BLD: update numpy_quaddtype licensing metadata to use PEP 639

Author: jorenham

quaddtype/pyproject.toml

@@ -1,7 +1,7 @@
 [build-system]
 requires = [
     "meson>=1.3.2",
-    "meson-python",
+    "meson-python>=0.18.0",
     "wheel",
     "numpy"
 ]
@@ -12,7 +12,8 @@ name = "numpy_quaddtype"
 description = "Quad (128-bit) float dtype for numpy"
 version = "0.2.0"
 readme = 'README.md'
-license = { file = "LICENSE" }
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
 authors = [{name = "Swayam Singh", email = "[email protected]"}]
 requires-python = ">=3.10.0"
 dependencies = [