Mark roadrunner 3.x as supported

[bwoebi]

First, roadrunner 3.x is supported.

However, some users have been confused because the SDK (https://github.com/roadrunner-php/http) is versioned differently from the web server (https://github.com/roadrunner-server/roadrunner). These are independent, but people have been asking for whether we support version "2024.2", while the real thing they would need to know is if we support Roadrunner SDK 3.x (but they don't really grasp that).

Is there anything we can do here to make this clearer to viewers of that documentation page?

Merge instructions

• [x] Please merge after reviewing