input: Write a python function to generate a random matrix with specified number of rows and columns.
  assert generate_random_matrix(3, 3).shape == (3, 3)
  assert generate_random_matrix(5, 2).shape == (5, 2)
  assert generate_random_matrix(4, 4).shape == (4, 4)
output: import numpy as np
  
  def generate_random_matrix(rows, cols):
      return np.random.rand(rows, cols)