input: Write a function to find the minimum and maximum values in an array.
  assert min_max([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == (1, 10)
  assert min_max([10, 20, 5, 7, 93, 84]) == (5, 93)
  assert min_max([-5, -7, 0, 8, 6, 4, 3]) == (-7, 8)
output: def min_max(arr):
      return (min(arr), max(arr))