Update to Spring Security 5.5.4

Closes gh-606

gradle/dependency-management.gradle

@@ -3,7 +3,7 @@ if (!project.hasProperty("springVersion")) {
 }
 
 if (!project.hasProperty("springSecurityVersion")) {
-	ext.springSecurityVersion = "5.5.3"
+	ext.springSecurityVersion = "5.5.4"
 }
 
 if (!project.hasProperty("reactorVersion")) {