Start building against Spring Security 4.0.3 snapshots

Closes gh-4263

spring-boot-dependencies/pom.xml

@@ -140,7 +140,7 @@
 		<spring-plugin.version>1.2.0.RELEASE</spring-plugin.version>
 		<spring-restdocs.version>1.0.0.RELEASE</spring-restdocs.version>
 		<spring-retry.version>1.1.2.RELEASE</spring-retry.version>
-		<spring-security.version>4.0.2.RELEASE</spring-security.version>
+		<spring-security.version>4.0.3.BUILD-SNAPSHOT</spring-security.version>
 		<spring-security-jwt.version>1.0.3.RELEASE</spring-security-jwt.version>
 		<spring-security-oauth.version>2.0.7.RELEASE</spring-security-oauth.version>
 		<spring-session.version>1.0.2.RELEASE</spring-session.version>