Designate connection string argument type as optional

[ajnelson-nist]

The signature for pyodbc.connect() designates the connection string as required. However, the implementation in src/pyodbcmodule.cpp mod_connect permits the string to be absent if there are no positional arguments, relying instead on only keyword arguments. The doc string in src/pyodbcmodule.cpp connect_doc also confirms the string may be optionally supplied.

This patch updates the type signature to reflect the implementation and documentation.

Signed-off-by: Alex Nelson alexander.nelson@nist.gov

[ajnelson-nist]

Thank you!