Modernize packaging and remove universal wheel option

Author: tilgovi

setup.cfg

@@ -1,6 +1,3 @@
-[bdist_wheel]
-universal = 1
-
 [easy_install]
 zip_ok = False
 

setup.py

@@ -37,9 +37,15 @@ def run_tests(self):
     version='0.4.3-dev',
     description='Pyramid OAuthLib integration',
     long_description=README + '\n\n' + CHANGES,
+    long_description_content_type="text/x-rst",
     classifiers=[
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3 :: Only",
         "Framework :: Pyramid",
         "Topic :: Internet :: WWW/HTTP",
         "Topic :: Internet :: WWW/HTTP :: WSGI :: Middleware",
@@ -53,6 +59,7 @@ def run_tests(self):
     include_package_data=True,
     install_requires=['pyramid>=1.4.0', 'oauthlib>=3'],
     packages=find_packages(),
+    python_requires='>=3.7',
     setup_requires=['setuptools_git'],
     tests_require=['mock', 'pytest', 'pytest-cov'],
     zip_safe=False,