Binary defaults for conditional metadata now used Binary Type

Before they were of String type

resolves #467

spring-cloud-task-core/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -1,7 +1,7 @@
 {
   "properties": [
     {
-      "defaultValue": "false",
+      "defaultValue": false,
       "name": "spring.cloud.task.single-instance-enabled",
       "description": "This property is used to determine if a task will execute if another task with the same app name is running.",
       "type": "java.lang.Boolean"