Prepare 19.6.0 release. #1309

Job	Run time
ruff	8s
sdist	3m 54s
mypy	29s
parse_sdl (macos-latest, 3.2.16)	24s
parse_sdl (windows-latest, 3.2.16)	1m 20s
test-docs	1m 59s
build (ubuntu-latest, pypy-3.10, x64)	6m 41s
build (ubuntu-latest, 3.10, x64)	8m 20s
tox (ubuntu-latest)	2m 14s
build (windows-latest, 3.10, x64)	3m 37s
linux-wheels (x86_64, pp310-manylinux*)	3m 28s
linux-wheels (aarch64, cp310-manylinux*)	4m 0s
build (windows-latest, pypy-3.10, x64)	3m 37s
build (windows-latest, 3.10, x86)	5m 56s
linux-wheels (x86_64, cp310-manylinux*)	4m 7s
build-macos (pp310-*)	4m 14s
build-macos (cp310-*_universal2)	1m 49s
linux-wheels (aarch64, pp310-manylinux*)	3m 54s
pyodide	5m 2s
publish	39s
	1h 5m 52s

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