manifest: Fix third_party/kernel branch to main-R105

BUG=b/268237065
TEST=None
RELEASE_NOTE=None

Change-Id: Ifd810e20f94b413564bde4314676c34ec82d1355
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/42167
Reviewed-by: He Gao <hegao@google.com>
Tested-by: Meena Shanmugam <meenashanmugam@google.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
diff --git a/external_full.xml b/external_full.xml
index accaa46..7be3bf5 100644
--- a/external_full.xml
+++ b/external_full.xml
@@ -112,10 +112,10 @@
            revision="refs/heads/release-R105" />
   <project path="src/third_party/kernel/v5.15"
            name="third_party/kernel"
-           revision="refs/heads/release-R105-cos-5.15" />
+           revision="refs/heads/main-R105-cos-5.15" />
   <project path="src/third_party/kernel/v6.1"
            name="third_party/kernel"
-           revision="refs/heads/release-R105-cos-6.1" />
+           revision="refs/heads/main-R105-cos-6.1" />
 
   <repo-hooks enabled-list="pre-upload"
            in-project="cos/repohooks" />