input: Write a python function to update the board with a player's move and then display the updated board.
  assert update_board(board, 1, 1, 'O') == [['_','_','_'], ['_','O','_'], ['_','_','_']]
  assert update_board(board, 2, 2, 'X') == [['_','_','_'], ['_','_','_'], ['_','_','X']]
  assert update_board(board, 0, 0, 'O') == [['O','_','_'], ['_','_','_'], ['_','_','_']]
output: def update_board(board, row, col, player):
      board[row][col] = player
      return board