Debian: prefer libayatana-appindicator3-dev

As of:
 - https://gerrit-ring.savoirfairelinux.com/9288

It is now prefered to build with libayatana-appindicator3-dev.

Change-Id: Ic42e019ada326a11d9c087558838374a1c75f652
Reviewed-by: Sebastien Blin <sebastien.blin@savoirfairelinux.com>

packaging/rules/debian/control

@@ -20,7 +20,7 @@ Build-Depends: debhelper (>= 9),
                qttools5-dev-tools,
                gettext,
                libqrencode-dev,
-               libappindicator3-dev,
+               libayatana-appindicator3-dev | libappindicator3-dev,
                libnm-dev,
                libwebkit2gtk-4.0-dev | libwebkit2gtk-3.0-dev,
 # ring-daemon