According to Wikipedia , phone numbers in Oman start with +968, then a 7 or a 9 followed by 7 digits. The current regex only allows 9 as a prefix, which fails with newer phone numbers. This PR adds the extra digit to be allowed.

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (where applicable)
• Tests written (where applicable)
• References provided in PR (where applicable)