Make the amber-phone version a backport of the byzantium version

This helps to keep things in sync by a simple merge from byzantium to amber-phone. Once that is in i'll

• move master to pureos/amber-phone
• make pureos/byzantium the default branch
• tag a pureos/33~amber0 release once v32 migrated from staging

Individual commit review is not that useful, it's better to compare to the v32 tag (which is the last revision for amber-phone without ~amber0.

This can serve as a reference for other packages (most of them will be simpler since the delta is even smaller).

We should consider using pureos/latest instead of pureos/<newest-suite> at some point but currently that would likely be more confusing so let's do that when byzantium becomes the default.

debian/changelog

+librem5-base (33) byzantium; urgency=medium
+
+  * Upload to byzantium
+  * d/gbp.conf: Update gbp.conf for Byzantium
+  * Add librsvg2-common.
+    Needed to render SVG from bullseye/byzantium on. This can go away
+    once we install recommends by default.
+  * gnome-base: Switch back to gnome-software.
+    Byzantium does not have PureOS Store yet
+  * d/control: Switch priority to optional.
+    Otherwise the laptop installer breaks
+  * gitlab-ci: Use PureOS byzantium.
+    This way we get packages suitable for byzantium
+  * tests: Test for librem5-gnome.
+    The dev package is not that important atm and we add it back
+    once more deps are in place
+  * gnome-all: Drop firefox-esr-mobile config.
+    Drop until it hits byzantium
+  * Revert "defaults: Lower priority for src:webkit for non-amber phone"
+    We just use the byzantium version
+    This reverts commit fbe0101c46a38de71b567b87bc18e8f832af4a59.
+
+ -- Guido Günther <agx@sigxcpu.org>  Thu, 07 Jan 2021 12:57:39 +0100
+
 librem5-base (32) amber-phone; urgency=medium
 
   * defaults: Lower priority for src:webkit for non-amber phone.
@@ -124,6 +148,15 @@ librem5-base (26) amber-phone; urgency=medium
 
  -- Guido Günther <agx@sigxcpu.org>  Fri, 30 Oct 2020 16:51:47 +0100
 
+librem5-base (25.0pureos0.1) byzantium; urgency=high
+
+  * Forward port to byzantium
+  * Remaining changes:
+    * d/gbp.conf: Update gbp.conf for Byzantium
+    * Add librsvg2-common.
+
+ -- Guido Günther <agx@sigxcpu.org>  Wed, 28 Oct 2020 09:33:14 +0100
+
 librem5-base (25) amber-phone; urgency=medium
 
   [ Sebastian Krzyszkowiak ]
@@ -142,6 +175,21 @@ librem5-base (25) amber-phone; urgency=medium
 
  -- Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>  Mon, 28 Sep 2020 22:07:59 +0200
 
+librem5-base (24.0pureos0.2) byzantium; urgency=medium
+
+  * d/gbp.conf: Update gbp.conf for Byzantium
+  * Add librsvg2-common.
+    Needed to render SVG from bullseye/byzantium on. This can go away
+    once we install recommends by default.
+
+ -- Guido Günther <agx@sigxcpu.org>  Tue, 22 Sep 2020 13:45:12 +0200
+
+librem5-base (24.0pureos0.1) byzantium; urgency=medium
+
+  * Upload to byzantium
+
+ -- Guido Günther <agx@sigxcpu.org>  Tue, 22 Sep 2020 09:14:09 +0200
+
 librem5-base (24) amber-phone; urgency=medium
 
   [ Sebastian Krzyszkowiak ]