SNOW-1457704: Allows write_pandas to pass Cursor in addition to Connection.

What is the current behavior?

You can pass Connection to write_pandas, but not Cursor.

with snowflake_conn.cursor() as cursor:
    df = cursor.execute("...").fetch_pandas_all()
    write_pandas(cursor.connection, df) # <- See this

What is the desired behavior?

Allow Cursor to be passed to write_pandas.

with snowflake_conn.cursor() as cursor:
    df = cursor.execute("...").fetch_pandas_all()
    write_pandas(cursor, df)

How would this improve snowflake-connector-python?

The write_pandas process can be described more intuitively while dealing with cursors using with.

References and other background

This is a minor modification, but we believe it is a natural writing permit given the definition of connection cursor in the PEP 249 – Python Database API.