title: gulp-watch in combination with gulp-less caching issue
body: <p>I have the following setup:</p>
  
  <pre><code>// watch for changes
  gulp.task('watch', function () {
    gulp.watch('./assets/**/*.less', ['compile-less']);
  });
  
  gulp.task("compile-less", () =&gt; {
      return gulp.src('./assets/build-packages/*.less')
      .pipe($.less({
          paths: [ $.path.join(__dirname, 'less', 'includes') ]
      }))
      .pipe(gulp.dest(OutputPath)); // ./dist/styles/
  });
  </code></pre>
  
  <p>So basically every time a developer changes something in a less file it runs the task 'compile-less'. The task 'compile-less' builds our package less files (including all the @imports). The first change in a random less file works, all the less files are being build. The second time it runs the task but my generated dist folder isn't updated when I change something to a less file that is imported. I'm wondering if the combination of the watch task and the compiling task somehow caches files. Because if I run the compile-less task manually it works everytime.</p>
  
  <p>Does anyone had the same experience?</p>