OWNERS: fix syntax

Two subdirectory OWNERS files had invalid syntax which caused the
tools to crash.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia7cef2eae99eaf6fbdddc099b2261e35862cb18e
diff --git a/subprojects/libcr51sign/OWNERS b/subprojects/libcr51sign/OWNERS
index 1dca102..4b1886a 100644
--- a/subprojects/libcr51sign/OWNERS
+++ b/subprojects/libcr51sign/OWNERS
@@ -1 +1,2 @@
-nanzhoumails@gmail.com
+owners:
+- nanzhoumails@gmail.com
diff --git a/subprojects/nemora-postd/OWNERS b/subprojects/nemora-postd/OWNERS
index 1dca102..4b1886a 100644
--- a/subprojects/nemora-postd/OWNERS
+++ b/subprojects/nemora-postd/OWNERS
@@ -1 +1,2 @@
-nanzhoumails@gmail.com
+owners:
+- nanzhoumails@gmail.com