D8WFC - Contact + Custom File Upload

One file only.
2 MB limit.
Allowed types: gif jpg png jpeg.
Custom Data
YAML
civicrm_1_contact_1_contact_first_name:
  '#type': textfield
  '#contact_type': individual
  '#form_key': civicrm_1_contact_1_contact_first_name
  '#extra':
    width: 20
  '#title': 'First Name'
civicrm_1_contact_1_contact_last_name:
  '#type': textfield
  '#contact_type': individual
  '#form_key': civicrm_1_contact_1_contact_last_name
  '#extra':
    width: 20
  '#title': 'Last Name'
civicrm_1_contact_1_cg1_custom_1:
  '#type': managed_file
  '#title': File
  '#max_filesize': '2'
  '#file_extensions': 'gif jpg png jpeg'
  '#data_type': File
  '#form_key': civicrm_1_contact_1_cg1_custom_1
  '#extra': {  }
buttons:
  '#type': buttons
  '#title': Buttons
  '#options':
    'Button 1': 'Button 1'
    'Button 2': 'Button 2'