Add self back to CODEOWNERS (#140080)

I'm back from leave.  Revert flutter/flutter#125337 but don't take back the `CODEOWNERS` file itself.

Author: jmagman

CODEOWNERS

@@ -7,3 +7,5 @@
 # Use git ls-files '<pattern>' without a / prefix to see the list of matching files.
 
 /packages/flutter_tools/pubspec.yaml @christopherfujino
+/packages/flutter_tools/templates/module/ios/ @jmagman
+/packages/flutter_tools/templates/**/Podfile* @jmagman