Fix postal code validation for france locality

[mash3al-29]

This PR adds a regular expression (regex) to validate French postal codes accurately. The regex is designed to ensure that postal codes match the valid formats as specified by the French postal system. This change was made to accommodate additional test cases for postal code validation.

The new regex pattern is:
/^(?:(?:0[1-9]|[1-8]\d|9[0-5])\d{3}|97[1-46]\d{2})$/

This pattern allows for postal codes in the ranges of 01000 to 95999 and the overseas departments.

For more information on French postal codes and their structure, refer to the official postal service documentation La Poste.

Checklist

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