fix tempfile and new output in conky module

[ntorresalberto]

This patch includes:

Fixes for 2 problems:

• Conky has a new output that should be ignored
  In my case, with conky 1.21.7-pre- (default version with latest Fedora) outputs conky: 'i3' x11 session running 'i3' desktop
• For some reason NamedTemporaryFile needs delete_on_close=False (which I thought was implied by delete=False, but apparently that is not the case)

A small refactor:

• renamed invalid_conky_errors to ignored_conky_outputs as they're actually just expected outputs that we don't care about (and not really runtime problems requiring a warning/exit/exception)

[lasers]

Code looks fine. Untested. Thank you for looking into this.

[ultrabug]

Thanks a lot @ntorresalberto and @lasers

[voh9eepah]

The latest Python for FreeBSD is 3.11, and there NamedTemporaryFile does not have a delete_on_close parameter.

However, with Python 3.11 the self.tmpfile = NamedTemporaryFile(prefix="py3status_conky-", suffix=".conf", delete=False) seems to work just fine.