[My Account] Add possibility to change Region via 'updateCustomerAddress' mutation

[naydav]

Preconditions:

• Customer is created
• Customer address is created

Steps:

• Perform mutation

mutation {
  createCustomerAddress(id: 'address id', input: {
    region: {
        region_id: 'some different from initial region id'
    }   
  }) {
    id
    region {
      region
      region_id
      region_code
    }    
  }
}

Actual: Region is not changed
Expected: Region is changed

[naydav]

#312