Release tracking PR: `v0.12.0` #525

Job	Run time
Test 32-bit version	26s
Check for changes to the public API	1m 21s
Cross test	1m 9s
Test - beta toolchain	23s
no_std no alloc	48s
no_std with alloc	48s
Test - 1.56.1 toolchain	2m 12s
Test - nightly toolchain	20s
Test - stable toolchain	24s
	7m 51s

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