Move OWNER reference master=>main.

BUG=b/291759353

Change-Id: Iada79f4fc74eb9894922304912e1b247e2fd01d1
diff --git a/OWNERS b/OWNERS
index 4de1e69..003b75c 100644
--- a/OWNERS
+++ b/OWNERS
@@ -5,4 +5,4 @@
 #
 # The kernel follows a different branching model than that of platform, which
 # needs the 'master' branch to be explicitly declared.
-include kernel/build:master:/kleaf/OWNERS
+include kernel/build:main:/kleaf/OWNERS