Create a function that takes a matrix of size (m, n) and returns a matrix of size (m+2, n+2) with a pad of 0s around the perimeter.
padMatrix([[]]) ➞ [[0, 0], [0, 0], [0, 0]]
padMatrix([[9]]) ➞ [
[0, 0, 0],
[0, 9, 0],
[0, 0, 0]
]
padMatrix([["hi", True]]) ➞ [
[0, 0, 0, 0],
[0, "hi", True, 0],
[0, 0, 0, 0]
]
padMatrix([
[1, 2, 5],
[8, 6, 7],
[3, 4, 9]
]) ➞ [
[0, 0, 0, 0, 0],
[0, 1, 2, 5, 0],
[0, 8, 6, 7, 0],
[0, 3, 4, 9, 0],
[0, 0, 0, 0, 0]
]