Add gustaf to audio/OWNERS

Bug: None
Change-Id: I1105c47ff642094730635dc3f00663d45dd57c6a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/157420
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29536}
diff --git a/audio/OWNERS b/audio/OWNERS
index d53e4fa..160699d 100644
--- a/audio/OWNERS
+++ b/audio/OWNERS
@@ -1,5 +1,6 @@
 solenberg@webrtc.org
 ossu@webrtc.org
+gustaf@webrtc.org
 
 # These are for the common case of adding or renaming files. If you're doing
 # structural changes, please get a review from a reviewer in this file.