rootdev: Add OWNERS file

This CL is populating OWNERS file based on the candidates in the Chrome OS OWNERS status sheet.

BUG=b:132095048
TEST=None

Change-Id: I91afc597bb60e32b008f13780868c4d9007bc058
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/rootdev/+/1682217

OWNERS

diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..ff83450
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,3 @@
+bmgordon@chromium.org
+xiaochu@chromium.org
+yunlian@google.com