Fix invalid IANA time zone identifier for Atlantic/Cape_Verde

[andrelaszlo]

Motivation / Background

Fixes: #2928

This Pull Request has been created because our tests using Faker time zones mostly pass, but fails when the Atlantic/Cabo_Verde time zone is returned. We validate that time zones are valid IANA identifiers, and Atlantic/Cabo_Verde is called Atlantic/Cape_Verde in the Time Zone Database.

Additional information

• Theory and pragmatics of the tz code and data - Timezone identifiers
• Time Zone Database
• Atlantic/Cape_Verde info in a more accessible (but unofficial) representation of the tzdb
• TZInfo::Timezone.all_identifiers - the time zones according to the tzinfo gem.
• ActiveSupport::TimeZone.all - the time zones according to Active Support, which uses the tzinfo gem as well.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug, refactor something, or add a feature.
• Tests and Rubocop are passing before submitting your proposed changes.

[andrelaszlo]

Unrelated, but I'm not sure it makes sense to translate the time zone names at all, since they're identifiers. Here's an example:

      time_zone: [África/Argel, África/Cairo, África/Casablanca, África/Harare, ...]

/faker/lib/locales/es-MX.yml:15

Each timezone has a name that uniquely identifies the timezone. Inexperienced users are not expected to select these names unaided. Distributors should provide documentation and/or a simple selection interface that explains each name via a map or via descriptive text like "Czech Republic" instead of the timezone name "Europe/Prague". If geolocation information is available, a selection interface can locate the user on a timezone map or prioritize names that are geographically close. For an example selection interface, see the tzselect program in the tz code. The Unicode Common Locale Data Repository contains data that may be useful for other selection interfaces; it maps timezone names like Europe/Prague to locale-dependent strings like "Prague", "Praha", "Прага", and "布拉格".

This quote from Theory and pragmatics of the tz code and data - Timezone identifiers hints that the timezone names can be mapped to translations, but the unique identifier aspect gets lost if the timezone's name itself is translated.

[thdaraujo]

excellent, thanks for adding tests!