Add `Array.update` or similar

[mbartlett21]

This would be useful for making modifications to individual items in an array.

I am currently using the below definition to do this:

{-| Updates the element at the given index using the provided function,
or returns the array unmodified if the index is out of bounds.

    arrayUpdate 1 (\a -> a * 10) [ 1, 2, 3 ] == [ 1, 20, 3 ]
    arrayUpdate 10 (\a -> a * 10) [ 1, 2, 3 ] == [ 1, 2, 3 ]

 -}
arrayUpdate : Int -> (a -> a) -> Array a -> Array a
arrayUpdate i f arr =
    case Array.get i arr of
        Just v ->
            Array.set i (f v) arr

        Nothing ->
            arr

[robinheghan]

Fixed in upcoming release.