Set MSRV to 1.70 (#279) #925

Job	Run time
rustfmt	3s
Cross build from macOS to Linux (FIPS) (x86_64-unknown-linux-gnu)	5m 0s
clippy	8m 10s
Cross build from macOS to Linux (x86_64-unknown-linux-gnu)	2m 11s
Test features	7m 21s
Test FIPS integration	3m 3s
Test (stable)	2m 10s
Test (arm-android)	2m 1s
Test (arm64-android)	1m 53s
Test (i686-android)	1m 55s
Test (x86_64-android)	2m 5s
Test (aarch64-ios)	2m 12s
Test (aarch64-ios-sim)	2m 12s
Test (x86_64-ios)	2m 14s
Test (i686-linux)	2m 18s
Test (arm-linux)	2m 32s
Test (aarch64-linux)	2m 15s
Test (arm64-macos)	2m 9s
Test (x86_64-macos)	2m 19s
Test (x86_64-mingw)	6m 36s
Test (i686-msvc)	6m 35s
Test (x86_64-msvc)	4m 25s
	1h 11m 39s

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