Make pre-commit hook script POSIX compliant

[adatzer]

Describe the bug

The pre-commit hook script uses $> /dev/null which is not POSIX compliant since it really intends > /dev/null 2>&1.

To Reproduce

Run the script where the standard command interpreter for the system is for example dash (e.g. Ubuntu):

#!/bin/sh

if ! command -v echo &> /dev/null
then
   echo 'not found'
else
   echo 'found'
fi

Output is:

not found
echo

Expected behavior

The script works as intended in all posix compliant shells.

Additional context
This can be a blocker for contributors as they need to run git commands with --no-verify, which even then is not guaranteed to work e.g. for interactive rebase.