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