Switch go Gulp 4 for builds

.gitignore

@@ -1,5 +1,6 @@
 # Do not index node.js modules that are used for building
 node_modules
+package-lock.json
 
 # Do not index releases
 release

gulpfile.js

@@ -35,13 +35,13 @@ gulp.task('get-composer', function(callback) {
 });
 
 // Install Composer dependencies
-gulp.task('composer-install', ['get-composer'], function(callback) {
+gulp.task('composer-install', gulp.series('get-composer', function(callback) {
     exec(config.phpBin + ' composer.phar install --no-dev', function(error, stdout, stderr) {
         callback(error ? stderr : null);
     });
-});
+}));
 
-gulp.task('prepare-release', ['composer-install'], function() {
+gulp.task('prepare-release', gulp.series('composer-install', function() {
     var version = require('./package.json').version;
 
     return eventStream.merge(
@@ -51,14 +51,12 @@ gulp.task('prepare-release', ['composer-install'], function() {
             .pipe(tar('jabber-plugin-' + version + '.tar'))
             .pipe(gzip())
     )
-    .pipe(chmod(644))
+    .pipe(chmod(0644))
     .pipe(gulp.dest('release'));
-});
+}));
 
 // Builds and packs plugins sources
-gulp.task('default', ['prepare-release'], function() {
+gulp.task('default', gulp.series('prepare-release'));
-    // The "default" task is just an alias for "prepare-release" task.
-});
 
 /**
  * Returns files stream with the plugin sources.

package.json

@@ -2,17 +2,17 @@
   "version": "0.0.1",
   "devDependencies": {
     "event-stream": "~3.1.7",
-    "gulp": "^3.9.1",
+    "gulp": "^4.0.0",
-    "gulp-chmod": "~1.2.0",
+    "gulp-chmod": "~3.0.0",
     "gulp-composer": "*",
     "gulp-gzip": "~0.0.8",
     "gulp-rename": "~1.2.0",
-    "gulp-tar": "~1.3.1",
+    "gulp-tar": "~3.1.0",
     "gulp-util": "*",
     "gulp-zip": "~2.0.2"
   },
   "dependencies": {
-    "gulp": "^3.9.1",
+    "gulp": "^4.0.0",
     "graceful-fs": "^4.1.11"
   }
 }