Upgrade to Spring Framework 5.2.0.M1

Fixes gh-16173

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

@@ -177,7 +177,7 @@
 		<snakeyaml.version>1.24</snakeyaml.version>
 		<solr.version>8.0.0</solr.version>
 		<!-- deprecated in favor of "spring-framework.version" -->
-		<spring.version>5.2.0.BUILD-SNAPSHOT</spring.version>
+		<spring.version>5.2.0.M1</spring.version>
 		<spring-amqp.version>2.1.5.RELEASE</spring-amqp.version>
 		<spring-batch.version>4.1.2.RELEASE</spring-batch.version>
 		<spring-cloud-connectors.version>2.0.5.RELEASE</spring-cloud-connectors.version>