Apply suggestion from @maximthomas

Author: maximthomas

openig-core/src/main/java/org/forgerock/openig/handler/MockDataGenerator.java

@@ -128,6 +128,7 @@ private static Object generateByFormat(final String format, final Schema<?> sche
             case "uri-reference":
                 return "/api/resource/" + FAKER.number().numberBetween(1, 9999);
             case "uuid":
+            case "guid":
                 return UUID.randomUUID().toString();
             case "ipv4":
                 return FAKER.internet().ipV4Address();