Bump LXQt build dependencies.

debian/changelog

@@ -3,6 +3,7 @@ liblxqt (0.15.0-0ubuntu1) UNRELEASED; urgency=medium
   * New upstream release.
     - Remove upstream patches fixing Mac OS X and Hurd builds.
     - Update upstream signing key.
+    - Bump LXQt build dependencies.
   * Run wrap-and-sort.
   * Add libkf5windowsystem-dev to build dependencies.
   * Full copyright update.

debian/control

@@ -12,11 +12,11 @@ Build-Depends: debhelper-compat (= 12),
                libpolkit-qt5-1-dev,
                libqt5svg5-dev,
                libqt5x11extras5-dev,
-               libqt5xdg-dev (>= 3.3.1~),
-               libqt5xdgiconloader-dev (>= 3.3.1~),
+               libqt5xdg-dev (>= 3.5.0),
+               libqt5xdgiconloader-dev (>= 3.5.0),
                libx11-dev,
                libxss-dev,
-               lxqt-build-tools (>= 0.6.0)
+               lxqt-build-tools (>= 0.7.0)
 Standards-Version: 4.5.0
 Vcs-Browser: https://phab.lubuntu.me/source/liblxqt/
 Vcs-Git: https://phab.lubuntu.me/source/liblxqt.git