Tests

Accept --manifest-path #1114

Job	Run time
incremental-mutants	3m 17s
build (macOS-latest, stable)	2m 53s
cargo-mutants	1h 16m 14s
build (macOS-latest, nightly)	2m 59s
build (macOS-latest, 1.70)	3m 19s
build (ubuntu-latest, stable)	1m 21s
build (ubuntu-latest, nightly)	1m 15s
build (ubuntu-latest, 1.70)	1m 43s
build (windows-latest, stable)	2m 31s
build (windows-latest, nightly)	2m 33s
build (windows-latest, 1.70)	2m 44s
	1h 40m 49s

Provide feedback