Add entry for 6.6 kernel in manifest

BUG=b/316205830
TEST=repo sync --manifest-name=$HOME/cos/manifest/external_full.xml
RELEASE_NOTE=None

Change-Id: Iaabdf68da61b305f9b217a59b1742f0ef9fcfd3d
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/67630
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Tested-by: Kevin Berry <kpberry@google.com>
diff --git a/external_full.xml b/external_full.xml
index 23cf3c4..649ef47 100644
--- a/external_full.xml
+++ b/external_full.xml
@@ -125,6 +125,9 @@
   <project path="src/third_party/kernel/v6.1"
            name="third_party/kernel"
            revision="refs/heads/cos-6.1" />
+  <project path="src/third_party/kernel/v6.6"
+           name="third_party/kernel"
+           revision="refs/heads/cos-6.6" />
 
   <repo-hooks enabled-list="pre-upload"
            in-project="cos/repohooks" />