Release v2022.9.20

What's Changed

• Remove iso8601 from vendored packages by @oz123 in #5346
• Remove --sequential by @oz123 in #5348
• Safer usages of pkg_resources by @matteius in #5350
• Replace usage of pipfile by @oz123 in #5339
• Migrate isort, mypy, and pytest config into pyproject.toml by @cclauss in #5361

Full Changelog: v2022.9.8...v2022.9.20