input: Write a python function to generate a two-dimensional array with zeros shapes.
  assert generate_zeros_array(3, 3) == [[0, 0, 0], [0, 0, 0], [0, 0, 0]]
  assert generate_zeros_array(2, 4) == [[0, 0, 0, 0], [0, 0, 0, 0]]
  assert generate_zeros_array(1, 5) == [[0, 0, 0, 0, 0]]
output: def generate_zeros_array(rows, cols):
      return [[0 for _ in range(cols)] for _ in range(rows)]