Continuous Integration (CI) is a widely adopted practice in software development to automatically verify code changes across diverse environments. However, executing the full test suite on every pull request update can lead to redundant runs, slower feedback loops, and inefficient utilization of CI resources. To address this issue, we introduce PrioTestCI, a prioritization technique within GitHub Actions that focuses on re-executing test cases that have previously failed. If these prioritized tests succeed, the remaining tests proceed; otherwise, the workflow terminates early, saving computation resources and providing early feedback to developers. PrioTestCI utilizes commit-to-commit test result tracking to inform future test runs, thereby reducing unnecessary repetition and accelerating validation cycles. We evaluated our technique on the Pytest project, a real-world open-source project with an extensive test matrix. PrioTestCI resulted in a CI runtime reduction of 1h57m39s compared to the normal workflow, with individual configuration improvements ranging from 63.75% to 91.94% (81.55% on average). Demo video: https://youtu.be/_3CF9LJdv0I?si=XyE_8mBnDxk1lMnD Repository: https://github.com/ShubhamDesai/CI-Optimization