Set appropriate file stat times (#763)

* Set appropriate file stat times

Since we are creating the destination file, it's our responsibility to set the file stat times.

* fix code style

index.js

@@ -99,6 +99,10 @@ const gulpSass = (options, sync) => through.obj((file, enc, cb) => { // eslint-d
     file.contents = sassObj.css; // eslint-disable-line no-param-reassign
     file.path = replaceExtension(file.path, '.css'); // eslint-disable-line no-param-reassign
 
+    if (file.stat) {
+      file.stat.atime = file.stat.mtime = file.stat.ctime = new Date(); // eslint-disable-line
+    }
+
     cb(null, file);
   };