Merge pull request #727 from caucik/fix-imports

refactor: update @nestjs/core imports to reference top level index.ts

lib/schedule.explorer.ts

@@ -1,7 +1,6 @@
 import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
-import { DiscoveryService } from '@nestjs/core';
+import { DiscoveryService, MetadataScanner } from '@nestjs/core';
 import { InstanceWrapper } from '@nestjs/core/injector/instance-wrapper';
-import { MetadataScanner } from '@nestjs/core/metadata-scanner';
 import { SchedulerType } from './enums/scheduler-type.enum';
 import { SchedulerMetadataAccessor } from './schedule-metadata.accessor';
 import { SchedulerOrchestrator } from './scheduler.orchestrator';