Fix CI build, introduce justfile #90

Job	Run time
Lint	23s
Test Linux (stable, x86_64)	16s
Test non-Linux (macos-latest, stable)	25s
Test Linux (stable, i686)	1m 5s
Test non-Linux (macos-latest, stable, --features const-generics)	26s
Test Linux (stable, sparc64)	1m 9s
Test non-Linux (windows-latest, stable)	2m 2s
Test Linux (stable, --features const-generics, x86_64)	27s
Test non-Linux (windows-latest, stable, --features const-generics)	1m 25s
Test Linux (stable, --features const-generics, i686)	1m 6s
Test Linux (stable, --features const-generics, sparc64)	1m 13s
Test Linux (beta, x86_64)	19s
Test Linux (beta, i686)	2m 7s
Test Linux (beta, sparc64)	1m 15s
Test Linux (beta, --features const-generics, x86_64)	20s
Test Linux (beta, --features const-generics, i686)	1m 15s
Test Linux (beta, --features const-generics, sparc64)	1m 15s
Test Linux (nightly, x86_64)	20s
Test Linux (nightly, i686)	1m 13s
Test Linux (nightly, sparc64)	1m 12s
Test Linux (nightly, --features const-generics, x86_64)	19s
Test Linux (nightly, --features const-generics, i686)	2m 15s
Test Linux (nightly, --features const-generics, sparc64)	1m 26s
Test Linux (1.37.0, x86_64)	17s
All Succeeded	4s
	23m 34s

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