Compat with CoAuthors Plus 3.5+

[douglas-johnson]

Co-Authors Plus 3.5 introduced block editor compatibility. https://github.com/Automattic/Co-Authors-Plus/releases/tag/3.5

To do that, the taxonomy used by Co-Authors Plus was opened up to the WordPress REST API. Well, that's what our plugin does too. CAP made some similar decisions, but they're not all identical.

For example, we used the rest_base coauthor and they used coauthors

We'll need to

• Update our plugin to match the default rest base.
• Update our systems that use this API to match the updated URLs.

There are likely to be other fixes as well. I will report them here after testing.

[douglas-johnson]

After removing our custom rest_base I tested these endpoints successfully:

GET /wp-json/wp/v2/coauthors/?search=:slug
GET /wp-json/wp/v2/coauthors/?order=desc&orderby=id
DEL /wp-json/wp/v2/coauthors/:id/?force=true
POST Create /wp-json/wp/v2/coauthors/
POST Update /wp-json/wp/v2/coauthors/:id/

I tested activating and deactivating our plugin, Co-Authors Plus worked normally in the editor for users with author, editor and admin permissions.