Invalid regex character class in ftp setup #576

Describe the bug
Was testing total upkeep update with the console open and saw the error below in the browser console:

To Reproduce
Steps to reproduce the behavior:

1. Go to admin dashboard
2. Click on 'Total Upkeep' → 'Settings'
3. Select 'Backup Storage'
4. Open developer console
5. Click to configure/update ftp settings
6. See error in console