Fix UnicodeDecodeError exceptions by using errors=replace

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
Publishbot exceptions are now logged in several lines

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
Fix missing username parameter in IRC connect

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>