lefthook install fails when no git is available

[JuliusHenke]

I currently need to install a project in a node:16-alpine CI environment and the npm install fails with:

> ... postinstall
> lefthook install -f
Error: exec: "git": executable file not found in $PATH
npm ERR! code 1

Could the lefthook install rather print a warning than fail with an error if no git executable was found?
An easy option to disable the lefthook install in CI could also be provided via the environment variable LEFTHOOK=0.

[mrexox]

You can also set the CI variable in the container: see docs for disabling lefthook install in CI