how to sign commit in hook model

I want to use the cz to sign commit, I tried add -s after cz, but it cannot work.

in git:
```
git commit -m "fix: xxx" -s
```

in git-cz with husky:
```
#!/bin/sh
. "$(dirname "$0")/_/husky.sh"

exec < /dev/tty && cz -s --hook || true
```