ci: update test coverage badge

Author: github-actions[bot]

README.md

@@ -1,6 +1,6 @@
 # Bedrock API
 
-![Coverage](https://img.shields.io/badge/coverage-38.6%25-red)
+![Coverage](https://img.shields.io/badge/coverage-35.3%25-red)
 
 **Bedrock API** is an HTTP service that coordinates **Bedrock tracing workloads** through REST APIs and internal event-driven communication.