If you don't want to install global npm-check-updates you can simply run that:
node -e "const pk = JSON.parse(require('fs').readFileSync('package.json', 'utf-8'));require('child_process').spawn('npm', ['install', ...Object.keys(Object.assign({},pk.dependencies, pk.devDependencies)).map(a=>a+'@latest')]).stdout.on('data', d=>console.log(d.toString()))"