feat(pipeline-task): 流水线任务日志订阅接口。

src/pipeline-tasks/models/pipeline-task-log-message.module.ts

@@ -1,7 +1,13 @@
 import { PipelineTask } from './../pipeline-task.entity';
+import { PipelineUnits } from '../enums/pipeline-units.enum';
+import { Field, HideField, ObjectType } from '@nestjs/graphql';
 
+@ObjectType()
 export class PipelineTaskLogMessage {
+  @HideField()
   task: PipelineTask;
+  @Field(() => PipelineUnits)
+  unit: PipelineUnits;
   time: Date;
   message: string;