gulp file syntax error

I have the following gulp file:

var gulp = require('gulp'),
    browserify = require('browserify'),
    babelify = require('babelify'),
    source = require('vinyl-source-stream'),
    gutil = require('gulp-util');
    cssnano = require('gulp-cssnano'),
    autoprefixer = require('gulp-autoprefixer'),
    sass = require('gulp-ruby-sass'),
    notify = require('gulp-notify'),
    eslint = require('gulp-eslint'),
    sourcemaps = require('gulp-sourcemaps');

gulp.task('sass', function () {
    return sass('scss/style.scss', { sourcemap: true })
        .on('error', sass.logError)

        .pipe(autoprefixer({
            browsers: ["last 4 versions", "Firefox >= 27", "Blackberry >= 7", "IE 8", "IE 9"],
            cascade: false
        }))
        .pipe(cssnano())

        // For inline sourcemaps
        .pipe(sourcemaps.write())

        // For file sourcemaps
        .pipe(sourcemaps.write('maps', {
            includeContent: false,
            sourceRoot: 'scss'
        }))

        .on('error', function(e) {
            console.log(e);
        })

        .pipe(gulp.dest("css"))

        .pipe(notify("SASS compilation complete: <%=file.relative%>"))

});

gulp.task('lint', () => {
    // ESLint ignores files with "node_modules" paths.
    // So, it's best to have gulp ignore the directory as well.
    // Also, Be sure to return the stream from the task;
    // Otherwise, the task may end before the stream has finished.
    return gulp.src(['./js/components/*.js'])
        // eslint() attaches the lint output to the "eslint" property
        // of the file object so it can be used by other modules.
        .pipe(eslint({configFile: 'eslint.json'}))
        // eslint.format() outputs the lint results to the console.
        // Alternatively use eslint.formatEach() (see Docs).
        .pipe(eslint.format())
        // To have the process exit with an error code (1) on
        // lint error, return the stream and pipe to failAfterError last.
        .pipe(eslint.failAfterError());
});


gulp.task('es6', function() {
    browserify({
        entries: './ES6/script.js',
        debug: true,
        transform: [babelify.configure({
          presets: ['es2015']
        })]
    })
    .transform(babelify)
    .on('error',gutil.log)
    .bundle()
    .on('error',gutil.log)
    .pipe(source('script.js'))
    .pipe(gulp.dest('js'));
});

gulp.task('watch',function() {
    gulp.watch('./ES6/script.js',{debounceDelay: 5000},['lint', 'es6'])
    gulp.watch("scss/style.scss", ['sass'])
});

gulp.task('default', ['lint', 'es6', 'sass', 'watch']);

and a package.json like so:

{
  "name": "",
  "version": "1.0.0",
  "description": " ",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": ""
  },
  "author": "",
  "license": "ISC",
  "homepage": "",
  "devDependencies": {
    "babel-preset-es2015": "^6.24.0",
    "babelify": "^7.3.0",
    "browserify": "^14.1.0",
    "gulp": "^3.9.1",
    "gulp-autoprefixer": "^3.1.1",
    "gulp-cssnano": "^2.1.2",
    "gulp-eslint": "^3.0.1",
    "gulp-notify": "^3.0.0",
    "gulp-ruby-sass": "^2.1.1",
    "gulp-sourcemaps": "^2.4.1",
    "gulp-util": "^3.0.8",
    "reflex-grid": "^1.5.0",
    "vinyl-source-stream": "^1.1.0"
  },
  "dependencies": {
    "core-js": "^2.4.1",
    "normalize.css": "^7.0.0"
  }
}

it works all fine on my machine, however when somebody runs "npm install" and then run "gulp" they get the following error:

gulpfile.js:42 gulp.task(‘lint’, () => {
                   ^
SyntaxError: Unexpected token )
    at exports.runInThisContext (vm.js:73:16)
    at Module._compile (module.js:443:25)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)

via Alex