Start building against Spring Security snapshots

See gh-9603

spring-boot-dependencies/pom.xml

@@ -166,7 +166,7 @@
 		<spring-plugin.version>1.2.0.RELEASE</spring-plugin.version>
 		<spring-restdocs.version>1.2.1.RELEASE</spring-restdocs.version>
 		<spring-retry.version>1.2.1.RELEASE</spring-retry.version>
-		<spring-security.version>5.0.0.M2</spring-security.version>
+		<spring-security.version>5.0.0.M3</spring-security.version>
 		<spring-security-jwt.version>1.0.8.RELEASE</spring-security-jwt.version>
 		<spring-security-oauth.version>2.1.1.RELEASE</spring-security-oauth.version>
 		<spring-session.version>2.0.0.BUILD-SNAPSHOT</spring-session.version>