Update to spring-cloud-stream to 4.2.0-SNAPSHOT

This updates SCSt to 4.2.0-SNAPSHOT as there was something
broken w/ running the sample binder under 4.2.0-M1.

Author: onobc

gradle/libs.versions.toml

@@ -24,7 +24,7 @@ mockito = "5.12.0"
 spring-dep-mgmt = "1.1.6"
 spring-boot = "3.4.0-SNAPSHOT"
 spring-boot-for-docs = "3.4.0-SNAPSHOT"
-spring-cloud-stream = "4.2.0-M1"
+spring-cloud-stream = "4.2.0-SNAPSHOT"
 spring-retry = "2.0.10"
 system-lambda = "1.2.1"
 testcontainers = "1.19.8"