Version 0.12.1

This fixes a regression on Windows when targeting 32-bit wheels on a 64-bit host. This reverts part of #1209. We have added 32-bit testing on Windows to our CI.

Fixes:

• Use CMAKE_GENERATOR(_PLATFORM) on Windows again by @henryiii in #1235

Documentation:

• Use newly fixed click-extra for admonitions by @henryiii in #1232
• show CI state of the main branch in the badge by @LecrisUT in #1236

Full Changelog: v0.12.0...v0.12.1