feat: add CPython 3.10 pre-release support (#675)

* Add CPython 3.10 support

* Fix logger displaying CPython 3.1 instead of 3.10

* Fix tests failing with CPython 3.10

* Use pytest instead of nose

* feat: --pre flag

Apply suggestions from code review

Co-authored-by: Matthieu Darbois <mayeut@users.noreply.github.com>

* fix: update Python update script to process beta versions

* refactor: prerelease-pythons

* Use `strtobool` to parse `CIBW_PRERELEASE_PYTHONS` env var

* Update python version filtering for universal2 & arm64

* Filter out CPython 3.10 and above for `test_manylinuxXXXX_only[manylinux1]` test

* Use CIBW_BUILD filtering rather than CIBW_SKIP for test_docker_images

* Use skip_patterns to filter out pre-releases

* Use `prerelease_pythons` instead of `pre`

* Reword `CIBW_PRERELEASE_PYTHONS` doc per review.

* Use `CIBW_PRERELEASE_PYTHONS: True` for usage example.

* Update `cibuildwheel --help` doc

* docs: add note on spec.filter

* Clean up the BuildSelector __repr__ by refactoring

* fix: remove platform variants for CIBW_PRERELEASE_PYTHONS

* docs: mention the flag

Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>
Co-authored-by: Joe Rickerby <joerick@mac.com>

cibuildwheel/__main__.py

@@ -132,6 +132,12 @@ def main() -> None:
         help="Do not report an error code if the build does not match any wheels.",
     )
 
+    parser.add_argument(
+        "--prerelease-pythons",
+        action="store_true",
+        help="Enable pre-release Python versions if available.",
+    )
+
     args = parser.parse_args()
 
     detect_obsolete_options()
@@ -206,6 +212,9 @@ def main() -> None:
     build_verbosity_str = get_option_from_environment(
         "CIBW_BUILD_VERBOSITY", platform=platform, default=""
     )
+    prerelease_pythons = args.prerelease_pythons or cibuildwheel.util.strtobool(
+        os.environ.get("CIBW_PRERELEASE_PYTHONS", "0")
+    )
 
     package_files = {"setup.py", "setup.cfg", "pyproject.toml"}
 
@@ -222,8 +231,12 @@ def main() -> None:
     ) or get_requires_python_str(package_dir)
     requires_python = None if requires_python_str is None else SpecifierSet(requires_python_str)
 
+    # Hardcode pre-releases here, current: Python 3.10
     build_selector = BuildSelector(
-        build_config=build_config, skip_config=skip_config, requires_python=requires_python
+        build_config=build_config,
+        skip_config=skip_config,
+        requires_python=requires_python,
+        prerelease_pythons=prerelease_pythons,
     )
     test_selector = TestSelector(skip_config=test_skip)