Update README.md

Author: rcalago

core-kotlin-modules/core-kotlin-concurrency-3/README.md

@@ -9,3 +9,4 @@ This module contains articles about concurrency in Kotlin.
 - [Difference Between single() and first() in Kotlin Flows](https://www.baeldung.com/kotlin/flows-single-vs-first)
 - [Scheduling Repeating Task in Kotlin](https://www.baeldung.com/kotlin/schedule-repeating-task)
 - [Async Exception Handling in Kotlin](https://www.baeldung.com/kotlin/coroutine-exception-handling)
+- [Combining Multiple Kotlin Flows](https://www.baeldung.com/kotlin/combining-multiple-flows)