Update media's mainline OWNERS

Bug: 201770269
Test: repo upload
Change-Id: I3b6cb7da5fe68c7f7cf9756c7df94e1a9a9f8295
diff --git a/apex/media/OWNERS b/apex/media/OWNERS
index 73f02d3..bed3895 100644
--- a/apex/media/OWNERS
+++ b/apex/media/OWNERS
@@ -8,3 +8,6 @@
 
 # go/android-fwk-media-solutions for info on areas of ownership.
 include platform/frameworks/av:/media/janitors/media_solutions_OWNERS
+
+# media reliability team packages/delivers the media mainline builds.
+include platform/frameworks/av:/media/janitors/reliability_mainline_OWNERS