Update contexthub OWNERS

Test: n/a
Change-Id: I2d23999f1dccf91cfcb21e612740f67f7beb7e58
diff --git a/contexthub/1.0/default/OWNERS b/contexthub/1.0/default/OWNERS
index 5373073..90c2330 100644
--- a/contexthub/1.0/default/OWNERS
+++ b/contexthub/1.0/default/OWNERS
@@ -1,4 +1,3 @@
-aarossig@google.com
 arthuri@google.com
 bduddie@google.com
-bstack@google.com
+stange@google.com