Add owners for enable-picture-in-picture flag

Change-Id: I27a55289aaf2f5a2ba4f504dfb97602b9a4418c6
Reviewed-on: https://chromium-review.googlesource.com/c/1345970Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/master@{#610190}

chrome/browser/flag-metadata.json

@@ -1568,7 +1568,7 @@
   },
   {
     "name": "enable-picture-in-picture",
-    // "owners": [ "your-team" ],
+    "owners": [ "beaufort.francois@gmail.com", "mlamouri", "media-dev" ],
     "expiry_milestone": 76
   },
   {