update to PyO3 0.21 final #4468

Job	Run time
coverage	3m 26s
test MSRV	2m 47s
test on ubuntu	2m 58s
test on macos	5m 21s
test 3.8	2m 21s
test on windows	4m 31s
test 3.9	2m 50s
lint	1m 52s
test-debug 3.11	1m 15s
test 3.10	2m 33s
test-debug pypy3.10	2m 9s
test 3.11	2m 57s
test 3.12	2m 58s
test-pydantic-integration	1m 31s
test pypy3.9	3m 4s
rust benchmarks	3m 40s
test pypy3.10	2m 56s
build sdist	15s
build-wasm-emscripten	3m 33s
build on ${{ matrix.os }} (${{ matrix.target }} - ${{ matrix.interpreter \|\| 'all' }}${{ (((matrix.os == 'linux') && format(' - {0}', (((matrix.manylinux == 'auto') && 'manylinux') \|\| matrix.manylinux))) \|\| '') }})	0s
build pgo-optimized on ${{ matrix.os }} / ${{ matrix.interpreter }}	0s
test build on ${{ matrix.target }}-${{ matrix.distro }}	0s
test build on ${{ matrix.os }}	0s
inspect-pypi-assets	0s
check	2s
release	0s
	52m 59s

Provide feedback