upgrade gulp tasks and add default task

README.md

@@ -110,8 +110,7 @@ merge the `style.css` with [devicon.css](./devicon.css) and follow the next step
 with a more elegant solution to support automated build processing.
 
 ### Build and minify stylesheet
-Run the following commands to build the resulting file `devicon.min.css`
+Run the following command to build the resulting file `devicon.min.css`
 ```bash
-gulp concat-css
-gulp minify-css
+gulp default
 ```

gulpfile.js

@@ -1,18 +1,23 @@
-var gulp = require('gulp');
+var gulp      = require('gulp');
 var minifyCSS = require('gulp-minify-css');
 var concatCss = require('gulp-concat-css');
-var plumber = require('gulp-plumber');
+var plumber   = require('gulp-plumber');
 
-gulp.task('concat-css', function () {
-  return gulp.src(['./devicon.css', './devicon-colors.css'])
-  .pipe(plumber())
-  .pipe(concatCss('./devicon.min.css'))
-  .pipe(gulp.dest('./'));
-});
 
-gulp.task('minify-css', function() {
-  return gulp.src('./devicon.min.css')
-  .pipe(plumber())
-  .pipe(minifyCSS())
-  .pipe(gulp.dest('./'))
-});
+function concat() {
+    return gulp.src(['./devicon.css', './devicon-alias.css', './devicon-colors.css'])
+        .pipe(plumber())
+        .pipe(concatCss('./devicon.min.css'))
+        .pipe(gulp.dest('./'));
+}
+
+function minify() {
+    return gulp.src('./devicon.min.css')
+        .pipe(plumber())
+        .pipe(minifyCSS())
+        .pipe(gulp.dest('./'))
+}
+
+exports.concat = concat;
+exports.minify = minify;
+exports.default = gulp.series(concat, minify);