Fix Kresus binary path in npm publication

On my computer it's kresus not kresus.js:

(builds)$ ls -l /tmp/bin/
total 0
lrwxrwxrwx 1 nicofrand users 40 juin  14 09:21 kresus -> ../lib/node_modules/kresus/bin/kresus.js

Is it the same for everyone now?