commitlint.sh: rather use result of 'npm i'

It could happen that someone modifies this .sh file in
the future, changing the `npm install` to not install
the proper package(s) anymore, but npx still works. By
changing it to use ./node_modules/ we force this line to
depend on the results of the previous line (so that it
has a raison-d'etre).

Author: knocte

commitlint.sh

@@ -5,6 +5,6 @@ set -euxo pipefail
 cd "$(dirname "$0")"
 npm install
 npm install conventional-changelog-conventionalcommits commitlint@latest
-npx commitlint --version
-npx commitlint $@
+./node_modules/commitlint/cli.js --version
+./node_modules/commitlint/cli.js $@
 cd ..