Add 'if-host-match' option to m_sslinfo oper autologin configuration.•••This adds an option to perform the source host check (which is usually
performed on manual oper login) in addition to the certificate fingerprint
check when automatically logging in opers upon connection to the ircd.
Refactor the sslqueries mode handler.•••This fixes a rare desync where a server with the sslmodes module
but without the sslinfo module could desync when a remote user on
a server with both enables the sslqueries mode.
Switch from the Ubuntu 16.04 image to the 18.04 Ubuntu image.•••The Argon2 PPA is broken again and I don't want to deal with the
stress of working out why. The 16.04 image is EOL soon (see
actions/virtual-environments/#1084) so switching off it is just
easier.