feat: replace the deprecated gulp-util package

fixes #43

Author: XhmikosR

index.js

@@ -1,5 +1,5 @@
 var inlineSource = require('inline-source'),
-    gutil = require('gulp-util'),
+    PluginError = require('plugin-error'),
     path = require('path'),
     through = require('through2');
 
@@ -17,7 +17,7 @@ function gulpInlineSource (options) {
         }
 
         if (file.isStream()) {
-            this.emit('error', new gutil.PluginError(PLUGIN_NAME, 'Streaming not supported'));
+            this.emit('error', new PluginError(PLUGIN_NAME, 'Streaming not supported'));
             return cb();
         }
 
@@ -34,7 +34,7 @@ function gulpInlineSource (options) {
 
         inlineSource(file.contents.toString(), fileOptions, function (err, html) {
             if (err) {
-                self.emit('error', new gutil.PluginError(PLUGIN_NAME, err));
+                self.emit('error', new PluginError(PLUGIN_NAME, err));
             } else {
                 file.contents = new Buffer(html || '');
                 self.push(file);

package.json

@@ -19,7 +19,7 @@
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "dependencies": {
-    "gulp-util": "~3.0.6",
+    "plugin-error": "~1.0.1",
     "inline-source": "~5.2.6",
     "through2": "~2.0.0"
   },
@@ -31,7 +31,8 @@
     "husky": "^0.13.3",
     "semantic-release": "^6.3.2",
     "tape": "^4.0.1",
-    "validate-commit-msg": "^2.12.1"
+    "validate-commit-msg": "^2.12.1",
+    "vinyl": "^2.1.0"
   },
   "config": {
     "commitizen": {

test/main.js

@@ -1,13 +1,13 @@
 'use strict';
 
 var path = require('path'),
-    gutil = require('gulp-util'),
+    Vinyl = require('vinyl'),
     fs = require('fs'),
     test = require('tape'),
     inlinesource = require('../');
 
 function getFile (filePath, contents) {
-    return new gutil.File({
+    return new Vinyl({
         path: filePath,
         base: path.dirname(filePath),
         contents: contents || fs.readFileSync(filePath)