In your git project download the script, change the name, made it executable and you can use it
wget https://gist.githubusercontent.com/themakunga/1ba3d397594d5f3fa298c547c14c82e2/raw/65b4a81eaef5ba30063f6f2954e3c87da11bd84d/prepare-commit-msg.py
mv ./prepare-commit-msg.py ./.git/hooks/prepare-commit-msg
chmod a+x ./.git/hooks/prepare-commit-msg