Fix: Faker::Number.hexadecimal should include characters within the range of [0-9a-f]

[alextaujenis]

Motivation / Background

This Pull Request has been created because Faker::Number.hexadecimal returns characters within the range of [0-9a-e], when it should return characters within the range of [0-9a-f]. The method is not producing the f character within the generated hexadecimal strings.

Additional Information

def hexadecimal(digits: 6)
  hex = ''
  digits.times { hex += rand(15).to_s(16) }
  hex
end

The current implementation (above) includes rand(15), which is not inclusive and only returns the range [0-14], when the implementation requires [0-15] in order to return the f character. Adjusting the current implementation to return rand(16).to_s(16) allows the Faker::Number.hexadecimal method to return strings within the full character range (including the letter f, which is equal to 15.to_s(16)).

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.
• Double-check the existing generators documentation to make sure the new generator you want to add doesn't already exist.
• You've reviewed and followed the Contributing guidelines.

[thdaraujo]

nice catch!