upgrade to gulp 4 and update others dev dependencies

.travis.yml

@@ -8,9 +8,9 @@ git:
 language: node_js
 
 node_js:
-  - 6
   - 8
   - 9
+  - 10
 
 dist: trusty
 sudo: false

gulpfile.babel.js

@@ -7,10 +7,6 @@ import gulp from 'gulp';
 // and attach them to the `plugins` object
 import plugins from 'gulp-load-plugins';
 
-// Temporary solution until gulp 4
-// https://github.com/gulpjs/gulp/issues/355
-import runSequence from 'run-sequence';
-
 import archiver from 'archiver';
 import glob from 'glob';
 import del from 'del';
@@ -20,19 +16,18 @@ import modernizr from 'modernizr';
 import pkg from './package.json';
 import modernizrConfig from './modernizr-config.json';
 
-
 const dirs = pkg['h5bp-configs'].directories;
 
 // ---------------------------------------------------------------------
 // | Helper tasks                                                      |
 // ---------------------------------------------------------------------
 
-gulp.task('archive:create_archive_dir', () => {
+gulp.task('archive:create_archive_dir', (done) => {
   fs.mkdirSync(path.resolve(dirs.archive), '0755');
+  done();
 });
 
 gulp.task('archive:zip', (done) => {
-
   const archiveName = path.resolve(dirs.archive, `${pkg.name}_v${pkg.version}.zip`);
   const zip = archiver('zip');
   const files = glob.sync('**/*.*', {
@@ -49,7 +44,6 @@ gulp.task('archive:zip', (done) => {
   output.on('close', done);
 
   files.forEach((file) => {
-
     const filePath = path.resolve(dirs.dist, file);
 
     // `zip.bulk` does not maintain the file
@@ -58,12 +52,11 @@ gulp.task('archive:zip', (done) => {
       'name': file,
       'mode': fs.statSync(filePath).mode
     });
-
   });
 
   zip.pipe(output);
   zip.finalize();
-
+  done();
 });
 
 gulp.task('clean', (done) => {
@@ -75,16 +68,6 @@ gulp.task('clean', (done) => {
   });
 });
 
-gulp.task('copy', [
-  'copy:.htaccess',
-  'copy:index.html',
-  'copy:jquery',
-  'copy:license',
-  'copy:main.css',
-  'copy:misc',
-  'copy:normalize'
-]);
-
 gulp.task('copy:.htaccess', () =>
   gulp.src('node_modules/apache-server-configs/dist/.htaccess')
     .pipe(plugins().replace(/# ErrorDocument/g, 'ErrorDocument'))
@@ -94,12 +77,12 @@ gulp.task('copy:.htaccess', () =>
 gulp.task('copy:index.html', () => {
   const hash = ssri.fromData(
     fs.readFileSync('node_modules/jquery/dist/jquery.min.js'),
-    {algorithms: ['sha256']}
+    { algorithms: ['sha256'] }
   );
   let version = pkg.devDependencies.jquery;
   let modernizrVersion = pkg.devDependencies.modernizr;
 
-  gulp.src(`${dirs.src}/index.html`)
+  return gulp.src(`${dirs.src}/index.html`)
     .pipe(plugins().replace(/{{JQUERY_VERSION}}/g, version))
     .pipe(plugins().replace(/{{MODERNIZR_VERSION}}/g, modernizrVersion))
     .pipe(plugins().replace(/{{JQUERY_SRI_HASH}}/g, hash.toString()))
@@ -120,75 +103,81 @@ gulp.task('copy:license', () =>
 gulp.task('copy:main.css', () => {
   const banner = `/*! HTML5 Boilerplate v${pkg.version} | ${pkg.license} License | ${pkg.homepage} */\n\n`;
 
-  gulp.src(`node_modules/main.css/dist/main.css`)
+  return gulp.src('node_modules/main.css/dist/main.css')
     .pipe(plugins().header(banner))
     .pipe(plugins().autoprefixer({
-      browsers: ['last 2 versions', 'ie >= 9', '> 1%'],
       cascade: false
     }))
     .pipe(gulp.dest(`${dirs.dist}/css`));
 });
 
 gulp.task('copy:misc', () =>
   gulp.src([
-
     // Copy all files
     `${dirs.src}/**/*`,
 
     // Exclude the following files
     // (other tasks will handle the copying of these files)
     `!${dirs.src}/css/main.css`,
     `!${dirs.src}/index.html`
-
   ], {
-
-    // Include hidden files by default
-    dot: true
-
-  }).pipe(gulp.dest(dirs.dist))
+      // Include hidden files by default
+      dot: true
+    }).pipe(gulp.dest(dirs.dist))
 );
 
 gulp.task('copy:normalize', () =>
   gulp.src('node_modules/normalize.css/normalize.css')
     .pipe(gulp.dest(`${dirs.dist}/css`))
 );
 
-gulp.task('modernizr', (done) =>{
-
+gulp.task('modernizr', (done) => {
   modernizr.build(modernizrConfig, (code) => {
     fs.writeFile(`${dirs.dist}/js/vendor/modernizr-${pkg.devDependencies.modernizr}.min.js`, code, done);
   });
-
 });
 
 gulp.task('lint:js', () =>
   gulp.src([
-    'gulpfile.js',
     `${dirs.src}/js/*.js`,
     `${dirs.test}/*.js`
   ]).pipe(plugins().jscs())
     .pipe(plugins().eslint())
     .pipe(plugins().eslint.failOnError())
 );
 
-
 // ---------------------------------------------------------------------
 // | Main tasks                                                        |
 // ---------------------------------------------------------------------
+gulp.task(
+  'copy',
+  gulp.series(
+    'copy:.htaccess',
+    'copy:index.html',
+    'copy:jquery',
+    'copy:license',
+    'copy:main.css',
+    'copy:misc',
+    'copy:normalize'
+  )
+);
+
+gulp.task(
+  'build',
+  gulp.series(
+    gulp.parallel('clean', 'lint:js'),
+    'copy',
+    'modernizr'
+  )
+);
 
-gulp.task('archive', (done) => {
-  runSequence(
+gulp.task(
+  'archive',
+  gulp.series(
     'build',
     'archive:create_archive_dir',
-    'archive:zip',
-    done);
-});
-
-gulp.task('build', (done) => {
-  runSequence(
-    ['clean', 'lint:js'],
-    'copy', 'modernizr',
-    done);
-});
+    'archive:zip'
+  )
+);
 
-gulp.task('default', ['build']);
+gulp.task('default', gulp.series('build'))