Move setuptools' packaging configuration from setup.py to setup.cfg

Move setuptools' packaging configuration from setup.py to setup.cfg to
simplify setup.py and make its packaging more dedeclarative.

Signed-off-by: Satoru SATOH <satoru.satoh@gmail.com>

setup.cfg

@@ -11,3 +11,54 @@ all-files = 1
 source-dir = docs
 build-dir = docs/_build
 warning-is-error = 1
+
+[metadata]
+keywords =
+  yaml
+  lint
+  linter
+  syntax
+  checker
+
+url = https://github.com/adrienverge/yamllint
+classifiers =
+  Development Status :: 5 - Production/Stable
+  Environment :: Console
+  Intended Audience :: Developers
+  License :: OSI Approved :: GNU General Public License v3 (GPLv3)
+  Programming Language :: Python :: 2
+  Programming Language :: Python :: 2.7
+  Programming Language :: Python :: 3
+  Programming Language :: Python :: 3.4
+  Programming Language :: Python :: 3.5
+  Programming Language :: Python :: 3.6
+  Programming Language :: Python :: 3.7
+  Programming Language :: Python :: 3.8
+  Topic :: Software Development
+  Topic :: Software Development :: Debuggers
+  Topic :: Software Development :: Quality Assurance
+  Topic :: Software Development :: Testing
+
+[options]
+packages = find:
+
+python_requires = >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*
+
+include_package_data = True
+install_requires =
+  pathspec >= 0.5.3
+  pyyaml
+
+test_suite = tests
+
+[options.packages.find]
+exclude =
+  tests
+  tests.*
+
+[options.package_data]
+yamllint = conf/*.yaml
+
+[options.entry_points]
+console_scripts =
+  yamllint = yamllint.cli:run