Reduce the max concurrent requests and max requests per second to 5. We bumped it to 10 before because it seemed to work well, but we're seeing rate-limit issues again.
* Try improving renovate issues with Maven Central rate limiting
Try not to make too many concurrent requests to Maven Central
The logs display rate limit responses followed by OK responses, which could mean we're hammering the Maven Central repo with too many concurrent requests
* Try not hitting Maven Central for `androidx` packages
This is now 7, which is higher than the max value (6) renovate adds by default, so they are *always* prioritised above the rest, even if renovate gets rate-limited.