Add region code and update docs for country code

[iamsahilsonawane]

Connection with issue(s)

Close #71

Solution description

There are two fields now in the phone number object now, i.e. country code (eg. 1, 64) and region code (eg. US, UK).

Screenshots or Videos

To Do

• [x] Read contributing guide
• [x] Check the original issue to confirm it is fully satisfied
• [x] Add solution description to help guide reviewers
• [ ] Add unit test to verify new or fixed behaviour
• [ ] If apply, add documentation to code properties and package readme

[deandreamatias]

The code its ok, but we need add this new property to new readme documentation

[iamsahilsonawane]

The code its ok, but we need add this new property to new readme documentation

Done