Update submodules: plugins (new commits)

plugins:
    43f326c Greg Holmes <greg@dmdirc.com>
            Move MainFrame initialisation out of constructor.

            Gerrit: http://gerrit.dmdirc.com/3320

    75c1f2d Greg Holmes <greg@dmdirc.com>
            Move more ui init code to swing ui initialiser.

            Depends-On: I9e67f7f9fbb479c13ff04fc237f2cb82c08a506c
            Gerrit: http://gerrit.dmdirc.com/3317

Change-Id: I6e40737169dcf5f751b35fb8158d1eefdc9a900b