updating angular core and cli

step 1 of update Angular 10 -> 11

pdb-js/src/app/limit-by/limit-by.component.spec.ts

@@ -1,4 +1,4 @@
-import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+import { ComponentFixture, TestBed, waitForAsync } from '@angular/core/testing';
 
 import { LimitByComponent } from './limit-by.component';
 
@@ -6,7 +6,7 @@ describe('LimitByComponent', () => {
   let component: LimitByComponent;
   let fixture: ComponentFixture<LimitByComponent>;
 
-  beforeEach(async(() => {
+  beforeEach(waitForAsync(() => {
     TestBed.configureTestingModule({
       declarations: [ LimitByComponent ]
     })