fix: migrate project.license to SPDX expression (#260)

Drop the deprecated License :: trove classifier and switch project.license
from the PEP 621 table form to an SPDX string expression, silencing the
setuptools >=77 deprecation warnings. Bump build-system to setuptools>=77
as required by the SPDX string form (PEP 639).

Author: patchwright

docs/changelog.rst

@@ -1,6 +1,12 @@
 Changelog
 ---------
 
+Unreleased
+~~~~~~~~~~
+* Migrate ``project.license`` to an SPDX expression and drop the deprecated
+  ``License ::`` trove classifier, silencing the ``setuptools >=77``
+  deprecation warning. (#260)
+
 v0.16.2
 ~~~~~~~
 * Add support for Python 3.13.

pyproject.toml

@@ -1,21 +1,20 @@
 [build-system]
-requires = ["setuptools>=61", "wheel", "setuptools_scm>=6.2"]
+requires = ["setuptools>=77", "wheel", "setuptools_scm>=6.2"]
 build-backend = "setuptools.build_meta"
 
 [project]
 name = "python-barcode"
 description = "Create standard barcodes with Python. No external modules needed. (optional Pillow support included)."
 readme = "README.rst"
 requires-python = ">=3.9"
-license = { text = "MIT" }
+license = "MIT"
 authors = [
   { name = "Hugo Osvaldo Barrera et al", email = "hugo@whynothugo.nl" }
 ]
 classifiers = [
   "Development Status :: 5 - Production/Stable",
   "Environment :: Console",
   "Intended Audience :: Developers",
-  "License :: OSI Approved :: MIT License",
   "Operating System :: OS Independent",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",