Expose rollout group dynamic flag via REST (#1691)

Signed-off-by: Marinov Avgustin <Avgustin.Marinov@bosch.com>

hawkbit-rest/hawkbit-mgmt-api/src/main/java/org/eclipse/hawkbit/mgmt/json/model/rolloutgroup/MgmtRolloutGroupResponseBody.java

@@ -84,6 +84,9 @@ public class MgmtRolloutGroupResponseBody extends MgmtRolloutGroup {
     @Schema(description = "Rollouts id", example = "63")
     private Long rolloutGroupId;
 
+    @Schema(description = "If the rollout group is dynamic", example = "false")
+    private boolean dynamic;
+
     @JsonProperty(required = true)
     @Schema(description = "The status of this rollout", example = "ready")
     private String status;