Start building against Spring Batch 4.2.0.RC1 snapshots

See gh-17347

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -179,7 +179,7 @@
 		<snakeyaml.version>1.24</snakeyaml.version>
 		<solr.version>8.0.0</solr.version>
 		<spring-amqp.version>2.2.0.M3</spring-amqp.version>
-		<spring-batch.version>4.2.0.M2</spring-batch.version>
+		<spring-batch.version>4.2.0.BUILD-SNAPSHOT</spring-batch.version>
 		<spring-cloud-connectors.version>2.0.5.RELEASE</spring-cloud-connectors.version>
 		<spring-data-releasetrain.version>Moore-BUILD-SNAPSHOT</spring-data-releasetrain.version>
 		<spring-framework.version>5.2.0.BUILD-SNAPSHOT</spring-framework.version>