Update dependency cibuildwheel to v2.21.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
cibuildwheel (changelog)	==2.20.0 -> ==2.21.0

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Release Notes

pypa/cibuildwheel (cibuildwheel)

v2.21.0

Compare Source

• ⚠️ Update CPython 3.12 to 3.12.6, which changes the macOS minimum deployment target on CPython 3.12 from macOS 10.9 to macOS 10.13 (#​1998)
• 🛠 Changes the behaviour when inheriting config-settings in TOML overrides - rather than extending each key, which is rarely useful, individual keys will override previously set values. (#​1803)
• 🛠 Update CPython 3.13 to 3.13.0rc2 (#​1998)
• ✨ Adds support for multiarch OCI images (#​1961)
• 🐛 Fixes some bugs building Linux wheels on macOS. (#​1961)
• ⚠️ Changes the minimum version of Docker/Podman to Docker API version 1.43, Podman API version 3. The only mainstream runner this should affect is Travis Graviton2 runners - if so you can upgrade your version of Docker. (#​1961)

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