Add dpranke as an OWNER to the top-level GN and GYP files for the GN migration.

(src/BUILD.gn and src/build).

Since he's the main one tracking the migration.

[email protected]
[email protected]
BUG=461019

Review URL: https://codereview.chromium.org/999523002

Cr-Commit-Position: refs/heads/master@{#319979}
diff --git a/OWNERS b/OWNERS
index 7a1fd79..9fe36ca 100644
--- a/OWNERS
+++ b/OWNERS
@@ -2,7 +2,9 @@
 [email protected]
 [email protected]
 [email protected]
+
 per-file .gitignore=*
+per-file [email protected]
 per-file DEPS=*
 per-file AUTHORS=*
 per-file WATCHLISTS=*