block-buffer: release v0.12.0 #1278

Job	Run time
x86 (x86_64-unknown-linux-gnu, 1.85.0)	24s
test-derive (stable)	30s
test-derive (1.85.0)	29s
cross (aarch64-unknown-linux-gnu, stable)	51s
x86 (x86_64-unknown-linux-gnu, stable)	24s
cross (aarch64-unknown-linux-gnu, 1.85.0)	44s
build (1.85.0, armv7a-none-eabi)	18s
build (1.85.0, thumbv7em-none-eabi)	14s
minimal-versions / minimal-versions	36s
build (1.85.0, wasm32-unknown-unknown)	15s
test (x86_64-apple-darwin, macos-latest, stable)	19s
build (stable, armv7a-none-eabi)	18s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.85.0)	14s
build (stable, wasm32-unknown-unknown)	18s
test (x86_64-pc-windows-msvc, windows-latest, 1.85.0)	36s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	20s
cross (powerpc-unknown-linux-gnu, 1.85.0)	48s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.85.0, sudo apt update && sudo apt install gcc-mult...	50s
build (stable, thumbv7em-none-eabi)	16s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	52s
test (x86_64-apple-darwin, macos-latest, 1.85.0)	23s
cross (powerpc-unknown-linux-gnu, stable)	44s
test (x86_64-pc-windows-msvc, windows-latest, stable)	43s
	11m 26s

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