Regex to detect credit card numbers.
This regex was created for the purposes of detecting potentially compromised credentials for the purposes of information security and not to be used for malicious purposes.
Based on data from https://www.freeformatter.com/credit-card-number-generator-validator.html
Currently only works for Visa, MasterCard, Discover, AmEx, JCB, Diners Club and only 16 digits (15 for AmEx, 14 for Diners Club Int'l)