Building locales fails on windows.

[DRoet]

I tried moving grapesjs-mjml to the cli, but having the following issue:

Issue is this line: https://github.com/artf/grapesjs-cli/blob/master/src/build.js#L29

Start building locale files...
(node:14876) UnhandledPromiseRejectionWarning: Error: Command failed: rm -rf locale
'rm' is not recognized as an internal or external command,
operable program or batch file.

    at ChildProcess.exithandler (child_process.js:308:12)
    at ChildProcess.emit (events.js:314:20)
    at ChildProcess.EventEmitter.emit (domain.js:486:12)
    at maybeClose (internal/child_process.js:1047:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:287:5)

Process finished with exit code 0

should probably use something like rimraf package to make it crossplatform