More Utility Functions

[vipul-dixit-2004]

We can add, 1.) Is valid phone number: (checks for valid mobile number entered, i.e. 10 numeric characters only) 2.)Date format Validator: (Verify if a string represents a valid date in a specific format.) 3.)Credit Card Number Validator(Using Luhn's algorithm) I have these in mind for the time being but will add more later. Kindly assign me this under JWoC 2024. Thank You

[Jagroop2001]

@vipul-dixit-2004 , go for it !!

[Jagroop2001]

https://github.com/Jagroop2001/validify-string/pull/8