build(deps): bump actions/checkout from 3 to 4 #1198

Job	Run time
Clang Tidy	11s
Build+test (clang, stable, ubuntu-20.04)	56s
Build+test (clang, beta, ubuntu-20.04)	1m 4s
Build+test (clang, nightly, ubuntu-20.04)	1m 6s
Build+test (clang, 1.60.0, ubuntu-20.04)	3m 43s
Build+test (gcc, stable, ubuntu-20.04)	48s
Build+test (gcc, beta, ubuntu-20.04)	1m 1s
Build+test (gcc, nightly, ubuntu-20.04)	58s
Build+test (gcc, 1.60.0, ubuntu-20.04)	4m 38s
Build+test (macos-latest, clang, stable)	1m 42s
Clippy nightly (optional)	28s
Clippy	36s
Check for documentation errors	25s
ensure-header-updated	1m 47s
Format	22s
Check minimum versions	33s
Miri	1m 15s
Windows	2m 50s
Windows CMake, Debug configuration	2m 42s
Windows CMake, Release configuration	3m 23s
Valgrind	1m 11s
	31m 39s

Provide feedback