Typo in setup.py of exercise 4.2

[zl17282651]

There is a typo in setup.py of exercise 4.2.

    entry_points={
        'console_scripts': [
            'exercise42 = exercise42_pkg.exercise_42:main'
        ],
    },

should be

    entry_points={
        'console_scripts': [
            'exercise42 = exercise42_pkg.exercise42:main'
        ],
    },

[roalgoal]

Thank you, the notebook has been updated.