Hello,

I've refactored the way the allCards variable is created/handled in isCreditCard:
It currently is manually hardcoding all of the previously already defined RegExp into one huge RegExp, that it later then checks against.

This is problematic, because:

• it adds unnecessary code duplication (you need to store the provider RegExps in two places: 1x on its own and 1x inside allCards
• (at least to my eyes) it is unreadable
• therefore it makes it a nightmare to update RegExps or add new providers

I've replace it with a dynamically created array with the RegExps from the cards object instead, which will make it a lot easier to maintain and update, when new providers are added:

• you only need to add the RegExp inside the cards object
• no manual copying of the RegExp necessary

Since we are now working with an array instead of one huge RegExp, I had to also change the last "else if":
There I am using the Array some() method, which checks if any of the items inside the array return true for a given function.

Checklist

• PR contains only changes related; no stray files, etc.
• [ ] README updated (where applicable)
• [ ] Tests written (where applicable)