meta-quanta: update Yocto compat for gatesgarth

The next release of Yocto is soon and most of the upstream
layers have switched support strings for it.  Support layer
compat for gatesgarth (current) and dunsfell (previous).

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ifd23689bef011fe349f615ae7521515f86a5d74a
diff --git a/conf/layer.conf b/conf/layer.conf
index 18308e7..8db4bd2 100644
--- a/conf/layer.conf
+++ b/conf/layer.conf
@@ -7,4 +7,4 @@
 
 BBFILE_COLLECTIONS += "quanta-layer"
 BBFILE_PATTERN_quanta-layer := "^${LAYERDIR}/"
-LAYERSERIES_COMPAT_quanta-layer = "warrior zeus dunfell"
+LAYERSERIES_COMPAT_quanta-layer = "dunfell gatesgarth"