setuptools: adopt PEP 639 license metadata (#1280)

* setuptools: adopt PEP 639 license metadata

Signed-off-by: Adam J. Stewart <ajstewart426@gmail.com>

* Remove deprecated license identifier

Signed-off-by: Adam J. Stewart <ajstewart426@gmail.com>

---------

Signed-off-by: Adam J. Stewart <ajstewart426@gmail.com>
Co-authored-by: Pavel Iakubovskii <qubvel@gmail.com>

Author: adamjstewart

pyproject.toml

@@ -1,16 +1,16 @@
 [build-system]
-requires = ['setuptools>=61']
+requires = ['setuptools>=77']
 build-backend = 'setuptools.build_meta'
 
 [project]
 name = 'segmentation_models_pytorch'
 description = 'Image segmentation models with pre-trained backbones. PyTorch.'
 readme = 'README.md'
 requires-python = '>=3.10'
-license = {file = 'LICENSE'}
+license = "MIT"
+license-files = ["LICENSE"]
 authors = [{name = 'Pavel Iakubovskii', email = 'qubvel@gmail.com'}]
 classifiers = [
-    'License :: OSI Approved :: MIT License',
     'Programming Language :: Python',
     'Programming Language :: Python :: 3',
     'Programming Language :: Python :: Implementation :: CPython',