Bump sphinxcontrib-towncrier from 0.4.0a0 to 0.5.0a0 #9983

Job	Run time
Linter	1m 8s
Generate llhttp sources	7s
Test (3.9, ubuntu, false)	6m 39s
Test (3.9, macos, false)	6m 55s
Benchmark	4m 36s
Test (3.9, windows, false)	9m 26s
Test (3.9, Y, ubuntu, false)	6m 4s
Test (3.10, ubuntu, false)	7m 15s
Test (3.10, macos, false)	7m 37s
Test (3.10, windows, false)	9m 42s
Test (3.10, Y, ubuntu, false)	7m 5s
Test (3.11, ubuntu, false)	7m 13s
Test (3.11, macos, false)	5m 43s
Test (3.11, windows, false)	10m 34s
Test (3.11, Y, ubuntu, false)	6m 50s
Test (3.12, ubuntu, false)	8m 15s
Test (3.12, macos, false)	9m 5s
Test (3.12, windows, false)	10m 23s
Test (3.12, Y, ubuntu, false)	8m 6s
Test (3.13, ubuntu, false)	6m 39s
Test (3.13, macos, false)	5m 53s
Test (3.13, windows, false)	7m 49s
Test (3.13, Y, ubuntu, false)	6m 25s
Test (pypy-3.9, Y, ubuntu, false)	7m 13s
check	2s
Pre-Deploy	0s
Build wheels on ${{ matrix.os }} ${{ matrix.qemu }} ${{ matrix.musl }}	0s
Tarball	0s
Deploy	0s
	2h 46m 44s

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