chore: test with Python 3.10 (#856)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

setup.cfg

@@ -7,7 +7,7 @@ long_description_content_type = text/markdown
 url = https://github.com/pypa/cibuildwheel
 author = Joe Rickerby
 author_email = joerick@mac.com
-license = BSD
+license = BSD-2-Clause
 license_file = LICENSE
 classifiers =
     Development Status :: 5 - Production/Stable
@@ -20,6 +20,7 @@ classifiers =
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Programming Language :: Python :: Implementation :: CPython
     Topic :: Software Development :: Build Tools
 keywords = ci,wheel,packaging,pypi,travis,appveyor,macos,linux,windows
@@ -40,6 +41,10 @@ python_requires = >=3.6
 include_package_data = True
 zip_safe = False
 
+[options.packages.find]
+include =
+    cibuildwheel
+
 [options.entry_points]
 console_scripts =
     cibuildwheel = cibuildwheel.__main__:main
@@ -47,10 +52,6 @@ console_scripts =
 [options.package_data]
 cibuildwheel = resources/*
 
-[options.packages.find]
-include =
-    cibuildwheel
-
 [flake8]
 ignore = E501,W503,E741,E226,B950,E203
 select = C,E,F,W,B,B9