Move OWNER reference master=>main.

BUG=b/291759353

Change-Id: Ib10ef066e27a32d195bafff09606e2ea4037bd83
diff --git a/OWNERS b/OWNERS
index 45dc4dd..5a2b844 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1 +1 @@
-include platform/prebuilts/rust:master:/OWNERS
+include platform/prebuilts/rust:main:/OWNERS