Bump msrv to 1.67 #1705

Job	Run time
Test CUDA support	47s
Test build-std (aarch64-tvos)	1m 38s
Clippy	17s
Test build-std (aarch64-tvos-sim)	1m 39s
MSRV (ubuntu-latest)	1m 55s
Rustfmt	17s
Test build-std (x86_64-tvos)	2m 13s
MSRV (windows-latest)	2m 23s
MSRV (macos-latest)	2m 8s
semver-checks	15s
Test (stable)	35s
Test (beta)	33s
Test (nightly)	40s
Test (linux32)	1m 29s
Test (macos)	2m 36s
Test (aarch64-macos)	1m 31s
Test (aarch64-ios)	50s
Test (win32)	1m 33s
Test (win64)	2m 32s
Test (mingw32)	1m 46s
Test (mingw64)	1m 21s
Test (windows-2019)	2m 34s
Test (windows-aarch64, windows-latest, stable, aarch64-pc-windows-msvc, --no-run)	2m 30s
Test (windows-clang, windows-2019, stable, x86_64-pc-windows-msvc, clang, clang++)	3m 10s
Test (windows-clang-cl, windows-2019, stable, x86_64-pc-windows-msvc, clang-cl, clang-cl)	3m 13s
	40m 25s

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