Add kwiberg@webrtc.org as root owner.

NOTRY=true

Review-Url: https://codereview.webrtc.org/2060923003
Cr-Commit-Position: refs/heads/master@{#13125}
diff --git a/OWNERS b/OWNERS
index 6da5c88..f1b4277 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,4 +1,5 @@
 henrika@webrtc.org
+kwiberg@webrtc.org
 mflodman@webrtc.org
 niklas.enbom@webrtc.org
 tina.legrand@webrtc.org