Version 2.21.0

• ⚠️ 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)