Build wheel against py3 only (#1098)

* Build wheel against py3 only

* put everything in setup.py
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 2a9acf1..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,2 +0,0 @@
-[bdist_wheel]
-universal = 1
diff --git a/setup.py b/setup.py
index 106d2b1..025ecda 100644
--- a/setup.py
+++ b/setup.py
@@ -52,6 +52,9 @@
       author='Google Inc.',
       maintainer='Bill Wendling',
       maintainer_email='morbo@google.com',
+      options={'bdist_wheel': {
+          'python_tag': 'py3'
+      }},
       packages=find_packages('.'),
       project_urls={
           'Source': 'https://github.com/google/yapf',
@@ -63,13 +66,12 @@
           'License :: OSI Approved :: Apache Software License',
           'Operating System :: OS Independent',
           'Programming Language :: Python',
-          'Programming Language :: Python :: 3',
+          'Programming Language :: Python :: 3 :: Only',
           'Programming Language :: Python :: 3.7',
           'Programming Language :: Python :: 3.8',
           'Programming Language :: Python :: 3.9',
           'Programming Language :: Python :: 3.10',
           'Programming Language :: Python :: 3.11',
-          'Programming Language :: Python :: 3 :: Only',
           'Topic :: Software Development :: Libraries :: Python Modules',
           'Topic :: Software Development :: Quality Assurance',
       ],