Export Row class in __init__.py

Hey!

Is your feature request related to a problem? Please describe.

Unable to type a row as Row.

Describe the solution you'd like

Add the Row class to __init__.py.

Additional context

Since this PR, the fetchall and fetchone functions are working correctly (Cursor class). For my part, I would also like to be able to type them so that I can pass them as parameters/function return types.