Write a program which takes a string as input and returns an array containing the position of any vowels in the input string.
- Vowels in this context refer to the letter a,e,i,o and u
- The position of both uppercase and lower case vowels should be returned
Mmmm => []
Test => [2]
Banana => [2,4,6]
Aardvark -> [1,2,6]