Fix PROPOSED=1 not enabling proposed for all needed components

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.711) UNRELEASED; urgency=medium
+
+  * auto/config: when running with PROPOSED=1, enable -proposed for all the
+    components we listed as required and not just the default set (main,
+    restricted).
+
+ -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Fri, 29 Jan 2021 01:33:07 +0100
+
 livecd-rootfs (2.710) hirsute; urgency=medium
 
   * esp: install grub in ubuntu bootloader id path, instead of removable.

live-build/auto/config

@@ -1166,7 +1166,7 @@ if [ "$PROPOSED" ]; then
 	. config/bootstrap
 
 	cat > config/archives/proposed.list.chroot << EOF
-deb $LB_PARENT_MIRROR_BINARY_VOLATILE $SUITE-proposed $LB_PARENT_ARCHIVE_AREAS
+deb $LB_PARENT_MIRROR_BINARY_VOLATILE $SUITE-proposed ${COMPONENTS:-${LB_PARENT_ARCHIVE_AREAS}}
 EOF
 	cp -a config/archives/proposed.list.chroot \
 	      config/archives/proposed.list.binary