Switch back to debian testing

unstable breaks too much to be useful for CI. To keep CI green, we
stop installing pacman-package-manager in the default images and disable
debian tools tree in CI.

.github/workflows/ci.yml

@@ -102,7 +102,8 @@ jobs:
           - ubuntu
         tools:
           - arch
-          - debian
+          # TODO: Re-enable once pacman-package-manager is back in testing
+          # - debian
           - fedora
           - opensuse
           - ubuntu
@@ -181,7 +182,5 @@ jobs:
             --verbose \
             -m integration \
             --distribution ${{ matrix.distro }} \
-            $([ "${{ matrix.distro }}" = "debian" ] && echo --release=unstable) \
-            $([ "${{ matrix.tools }}" = "debian" ] && echo --tools-tree-release=unstable) \
             --tools-tree-distribution ${{ matrix.tools }} \
             tests/

mkosi.conf.d/20-debian/mkosi.conf

@@ -4,7 +4,7 @@
 Distribution=debian
 
 [Distribution]
-@Release=unstable
+@Release=testing
 Repositories=non-free-firmware
 
 [Content]

mkosi.conf.d/30-debian-ubuntu/mkosi.conf.d/20-not-focal.conf

@@ -9,6 +9,7 @@ Packages=
         archlinux-keyring
         dbus-broker
         dnf
-        makepkg
-        pacman-package-manager
+        # TODO: Add back once pacman-package-manager is back in testing
+        # makepkg
+        # pacman-package-manager
         swtpm