Prepare 21.2.0 release. #1436

Job	Run time
sdist	1m 5s
mypy	23s
ruff	6s
parse_sdl (windows-latest, 3.2.16)	41s
parse_sdl (macos-latest, 3.2.16)	31s
test-docs	1m 53s
pyodide	2m 51s
tox (ubuntu-latest)	2m 5s
build-macos (cp314t-*_universal2)	2m 17s
build-macos (cp310-*_universal2)	1m 58s
build-macos (pp310-*)	3m 39s
linux-wheels (x86_64, cp314t-manylinux*)	4m 29s
linux-wheels (x86_64, cp310-manylinux*)	4m 18s
linux-wheels (aarch64, pp310-manylinux*)	3m 35s
linux-wheels (x86_64, pp310-manylinux*)	4m 4s
linux-wheels (aarch64, cp314t-manylinux*)	3m 58s
linux-wheels (aarch64, cp310-manylinux*)	4m 15s
build (windows-11-arm, 3.11, arm64)	4m 26s
build (windows-latest, pypy-3.10, x64)	3m 40s
build (ubuntu-latest, pypy-3.10, x64)	3m 10s
build (windows-11-arm, 3.14t, arm64)	4m 51s
build (ubuntu-latest, 3.10, x64)	3m 46s
build (windows-latest, 3.14t, x86)	3m 29s
build (windows-latest, 3.10, x64)	3m 11s
build (windows-latest, 3.10, x86)	3m 41s
build (windows-latest, 3.14t, x64)	3m 57s
build (ubuntu-latest, 3.14t, x64)	3m 36s
publish	0s
	1h 19m 55s

Provide feedback