fix: open() takes 3 positional arguments but 4 were given

[thuchet-u]

Error since python 3.9 - open() takes 3 positional arguments but 4 were given
Inspired by mjs/imapclient#425

[lasselindqvist]

I found that in https://docs.python.org/3/library/imaplib.html#imaplib.IMAP4 and in https://docs.python.org/3/library/imaplib.html#imaplib.IMAP4.open specifically timeout parameter is now possible.
But in this PR I don't see us using the timeout parameter in any sensible way. We don't get it from anything or pass it to the socks module anywhere.