remove gutil using code

package.json

 {
   "name": "gitlab-artifact-dep",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Manages node.js package dependency towards Gitlab artifacts.",
   "main": "src/index.js",
   "repository": "ssh://git@git.elicer.io:2201/elice/gitlab-artifact-dep.git",

src/index.js

@@ -66,7 +66,7 @@ function download(url, token, dest, attemptCount) {
           if (count < MAX_DOWNLOAD_COUNT) {
             const message = (`Requested GitLab artifact does not exist. `
               + `Installer will try to download again in ${DOWNLOAD_SLEEP_DURATION / 1000} seconds.`);
-            gutil.log(message);
+            log(message);
 
             setTimeout(() => {
               download(url, token, dest, count + 1).then(val => {
@@ -195,7 +195,7 @@ function yarn(arg, cwd, cb) {
   }
   script.on('exit', function (code) {
     if (code !== 0) {
-      throw new gutil.PluginError('gitlab', `Failed on running Yarn with "${arg}" at "${cwd}".`);
+      throw `Failed on running Yarn with "${arg}" at "${cwd}".`;
     }
     cb(code);
   });
@@ -205,7 +205,7 @@ function removePeerDependencies(project) {
   return new Promise((resolve, reject) => {
     const packageInfo = JSON.parse(fs.readFileSync(`${project.path}/package.json`, 'utf8', function (err) {
       if (err) {
-        console.log(`No package.json found in "${project.path}".`);
+        log(`No package.json found in "${project.path}".`);
       }
     }));
     if (packageInfo) {