v2.21.0

What's Changed

• feat: add rate limit error class by @drish in https://github.com/resend/resend-python/pull/178
• chore(deps): update actions/checkout action to v6 by @renovate[bot] in https://github.com/resend/resend-python/pull/180
• chore(deps): update python docker tag to v3.14.2 by @renovate[bot] in https://github.com/resend/resend-python/pull/168
• feat: support for send/scheduled_at in broadcasts by @drish in https://github.com/resend/resend-python/pull/181
• chore: bump to v2.21.0 by @drish in https://github.com/resend/resend-python/pull/182

Full Changelog: https://github.com/resend/resend-python/compare/v2.19.0...v2.21.0