Update submodules: plugins (new commits)

plugins:
    f680720 Chris Smith <chris@dmdirc.com>
            Remove a bunch of deprecated methods.

            Depends-On: I06531664f45d26298d989b9ac82d614c67da8c55
            Gerrit: http://gerrit.dmdirc.com/2775

Change-Id: I0e4344c2b2817cf5eb8df1d2880fabb7d5bfdfaf
Remove a load of deprecated methods.

Change-Id: I06531664f45d26298d989b9ac82d614c67da8c55
Depends-On: Ia4cf947dd33272021b10d2dc4093f383277eefd2
Reviewed-on: http://gerrit.dmdirc.com/2773
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>