Create Regex Patterns

[mclancy96]

This pull request refactors several regex-based utility methods in lib/regex_lab.rb to improve readability and ensure consistent return types. The changes replace implicit return values with explicit boolean conversions and simplify the regex patterns for clarity.

Regex method improvements:

• starts_with_a_vowel?: Updated to explicitly return a boolean by using !! and simplified the regex to match words starting with a vowel.
• words_starting_with_un_and_ending_with_ing: Simplified the regex to scan for words starting with "un" and ending with "ing" using word boundaries.
• words_five_letters_long: Adjusted the regex to match exactly five-letter words using word boundaries and case-insensitive matching.
• first_word_capitalized_and_ends_with_punctuation?: Added !! for explicit boolean conversion and refined the regex to check for a capitalized first word and ending punctuation.
• valid_phone_number?: Ensured consistent return type with !! and updated the regex to match valid phone number patterns more flexibly.