@servo is currently experiencing luxury problems: because of so many new contributors helping out, our CI time has increased significantly. Before we could merge within 45 minutes, now the average is 3,5 hours.
Based on our analysis, the MacOS runners are the bottleneck. To add more of these runners, extra funding is needed.
If you want to help out Servo, consider donating at https://opencollective.com/servo so we can improve our CI time. Thanks everyone for their interest in the project!