Make Cython an optinal dependency. Update pyproject.toml and setup.py.

Resolves #166

Author: rushter

pyproject.toml

@@ -13,13 +13,13 @@ version = '0.3.30'
 description = 'Fast HTML5 parser with CSS selectors.'
 readme = 'README.rst'
 requires-python = '>=3.9'
-license = { file = 'LICENSE' }
+license = {text = 'MIT'}
 authors = [
     { name = 'Artem Golubin', email = 'me@rushter.com' }
 ]
 dependencies = [
-    "Cython",
 ]
+
 keywords = [
     "selectolax",
     "html",
@@ -33,7 +33,6 @@ classifiers = [
     "Topic :: Internet",
     "Topic :: Internet :: WWW/HTTP",
     "Intended Audience :: Developers",
-    "License :: OSI Approved :: MIT License",
     "Natural Language :: English",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.9",

setup.py

@@ -176,11 +176,6 @@ def make_extensions():
     packages=find_packages(include=["selectolax"]),
     package_data={"selectolax": ["py.typed"]},
     include_package_data=True,
-    license="MIT license",
     zip_safe=False,
-    test_suite="tests",
-    tests_require=[
-        "pytest",
-    ],
     ext_modules=make_extensions(),
 )