Add brianperry as coordinator for the decoupled menus initiative

Patch looks good :) Excited to take on this role within the initiative!

New initiative leads needs sign-off from Dries, so assigning to him.

I'm +1 with @brianperry becoming the initiative lead. Thank you, Brian!

Thanks @Dries!

The one other thing we need here is @brianperry to explicitly indicate that he has read the maintainer handbook at https://www.drupal.org/contribute/core/maintainers#maintainer-definition and particularly the responsibilities of the initiative coordinator https://www.drupal.org/contribute/core/maintainers#initiative, and to indicate that he understands and accepts those responsibilities.

Thanks for volunteering for this role!

I did read the maintainer handbook and the expectations for the initiative coordinator prior to offering to take on this role. I understand and accept those responsibilities.

Thanks all - excited about the future of this initiative!

Setting to RTBC.

Committed to 9.3.x and cherry-picked to 9.2.x. Yay!