[owners] Add OWNERs files to double-conversion

Change-Id: I5dc7a616bf219a4a1f9e74e0d971bc86d8d95537
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..5d4bbf7
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,4 @@
+brettw@google.com
+sadmac@google.com
+
+# COMPONENT: Tools>zxdb