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

@@ -6,7 +6,7 @@ var eventStream = require('event-stream'),
     gzip = require('gulp-gzip'),
     rename = require('gulp-rename');
 
-gulp.task('prepare-release', [], function() {
+gulp.task('prepare-release', function() {
     var version = require('./package.json').version;
 
     return eventStream.merge(
@@ -21,9 +21,7 @@ gulp.task('prepare-release', [], function() {
 });
 
 // Builds and packs plugins sources
-gulp.task('default', ['prepare-release'], function() {
-    // The "default" task is just an alias for "prepare-release" task.
-});
+gulp.task('default', gulp.series('prepare-release'));
 
 /**
  * Returns files stream with the plugin sources.

package.json

@@ -1,12 +1,12 @@
 {
     "version": "0.1.1",
     "devDependencies": {
-        "gulp": ">3.8.10",
-        "event-stream": ">3.1.7",
-        "gulp-zip": ">2.0.2",
-        "gulp-tar": ">1.3.1",
-        "gulp-gzip": ">0.0.8",
-        "gulp-chmod": ">1.2.0",
-        "gulp-rename": ">1.2.0"
+        "gulp": "~4.0.0",
+        "event-stream": "~3.1.7",
+        "gulp-zip": "~2.0.2",
+        "gulp-tar": "~3.1.0",
+        "gulp-gzip": "~0.0.8",
+        "gulp-chmod": "~3.0.0",
+        "gulp-rename": "~1.2.0"
     }
-}
+}