Pin a specific nightly #1264

Job	Run time
Clippy nightly (optional)	1s
Clang Tidy	8s
Build+test (clang, stable, ubuntu-20.04)	44s
Build+test (clang, beta, ubuntu-20.04)	42s
Clippy	17s
Check for documentation errors	1s
Build+test (clang, nightly-2023-11-01, ubuntu-20.04)	42s
ensure-header-updated	57s
Format	14s
Build+test (clang, 1.61.0, ubuntu-20.04)	4m 13s
Check minimum versions	1s
Build+test (gcc, stable, ubuntu-20.04)	40s
Windows	2m 21s
Build+test (gcc, beta, ubuntu-20.04)	36s
Miri	1s
Windows CMake, Debug configuration	1s
Build+test (gcc, nightly-2023-11-01, ubuntu-20.04)	30s
Windows CMake, Release configuration	1s
Build+test (gcc, 1.61.0, ubuntu-20.04)	4m 8s
Valgrind	1m 11s
Build+test (macos-latest, clang, stable)	1m 51s
	19m 20s

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