Expose whisper.cpp version as a static string #304

Job	Run time
rustfmt	16s
build (ubuntu-latest, stable)	1m 7s
clippy (ubuntu-latest, stable)	57s
build (ubuntu-latest, nightly)	50s
clippy (ubuntu-latest, nightly)	1m 20s
build (windows-latest, stable)	3m 42s
clippy (windows-latest, stable)	4m 6s
build (windows-latest, nightly)	3m 36s
clippy (windows-latest, nightly)	4m 47s
build (macos-latest, stable)	54s
clippy (macos-latest, stable)	1m 6s
build (macos-latest, nightly)	56s
clippy (macos-latest, nightly)	54s
	24m 31s

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