Given list of strings and a string return index of th value in the list or -1 if value was not found.
| Challenge | Solution |
Don’t use any Kotlin build-in methods that are directly returning index of element like indexOf / lastIndexOf /
indexOfFirst / indexOfLast, etc.
getIndex(listOf("A", "B", "C"), "A") // 0
getIndex(listOf("A", "B", "C"), "B") // 1
getIndex(listOf("A", "B", "C"), "D") // -1