dconf: update to 0.30.1.

Changes in dconf 0.30.1
=======================

 - Engine: Fix memory leak when subscribing to a path
   (Guido G端nther; !25)

Changes in dconf 0.30.0
=======================

None.

Changes in dconf 0.29.2
=======================

 - Service: When corrupt GVDB files are found, they are now
   transparently backed up and replaced with an empty database.
   (Philip Withnall, !8)
 - Replace all hard-coded /etc path with sysconfdir. This is useful for
   JHBuild environments and systems that don't want to use /etc/dconf.
   (Ting-Wei Lan; !21, #739229)
 - Engine: Change overflow thresholds in subscription counts from
   GMAXUINT32 to GMAXUINT (Daniel Playfair Cal; !20)
 - Change meson flag used to build Gtk-Doc from enable-gtk-doc to
   gtk_doc (Daniel Playfair Cal; !19)
 - Declare libdconf_service as a dependency to fix the build in
   massively parallelised environments (Emmanuele Bassi; !22)

Changes in dconf 0.29.1
=======================

 - Engine: track in progress watch handles to avoid spurious changed
   signals for the root path. Subscription requests are no longer sent
   if the engine is already subscribed to the given path. In the case
   that some value changes while a subscription request is in progress,
   a changed signal is only sent for the path being subscribed to
   instead of the root path. (Daniel Playfair Cal; !1, !5, #790640)

 - Engine: fix deadlock which occured when using the engine from libsoup
   within flatpak by extending the existing workaround for Glib !541, aka
   #674885. GSocket and various other GObject types are now also
   initialised in the main thread. (Owen Taylor; !15)

 - Add transfer annotations to the GTK-Doc strings for functions in the
   dconf_changeset_* and dconf_client_* namespaces (Xavier Claessens,
   Philip Withnall; !9, #758903)

 - Update GVDB subtree from GVDB master, containing mostly documentation
   improvements (Philip Withnall; !17)

 - dconf-update.vala: correct error message grammar (Kenyon Ralph; !6)

 - Various meson related improvements (I単igo Mart鱈nez; !11)

 - Add GitLab CI (Philip Withnall; !10)

 - Service: Port from the deprecated g_type_class_add_private() to
   G_ADD_PRIVATE() (Philip Withnall; !7)

 - Add Daniel Playfair Cal and Philip Withnall as maintainers (Philip
   Withnall)


(wiz)