Write a regular expression that matches any valid Canadian postal code with any of the following formats:
A1A 1A1
A1A-1A1
A1A1B1
Make the match case insensitive.
"M3M 0A9" ➞ true
"m4c-1t1" ➞ true
"m45 1t1" ➞ false
"M4C-1T1Z" ➞ false
This challenge is designed to use Regex only.