Gulp 4 workaround for updating atime and mtime on dest files.

mtime.js

// npm install --save-dev through2
import through2 from 'through2'

// Add this pipe before your gulp.dest() call
// ...
.pipe(through2.obj(function(file, enc, cb) {
  var date = new Date()
  file.stat.atime = date
  file.stat.mtime = date
  cb(null, file)
}))
// ...

Thanks to @WraithKenny for this workaround!