title: Cannot find module '@uirouter/core' on Angular 8 project with UIRouter
body: <p>When I create a new angular project with angular-cli, after installing the UIRotuer package through <code>npm install @uirouter/angular</code> and importing the module into the <code>app.module.ts</code> imports array, I get the error I show in the photo .</p>
  
  <p>Error: <a href="https://imgur.com/xaY3Zu9" rel="nofollow noreferrer">https://imgur.com/xaY3Zu9</a></p>
  
  <pre><code>
  ERROR in node_modules/@uirouter/angular/directives/uiSref.d.ts:3:63 - error TS2307: Cannot find module '@uirouter/core'.
  
  3 import { UIRouter, Obj, TransitionOptions, TargetState } from '@uirouter/core';
                                                                  ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/directives/uiSrefStatus.d.ts:5:46 - error TS2307: Cannot find module '@uirouter/core'.
  
  5 import { TargetState, UIRouterGlobals } from '@uirouter/core';
                                                 ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/directives/uiView.d.ts:4:69 - error TS2307: Cannot find module '@uirouter/core'.
  
  4 import { StateDeclaration, UIRouter, ViewConfig, ViewContext } from '@uirouter/core';
                                                                        ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/index.d.ts:10:15 - error TS2307: Cannot find module '@uirouter/core'.
  
  10 export * from '@uirouter/core';
                   ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/interface.d.ts:3:76 - error TS2307: Cannot find module '@uirouter/core'.
  
  3 import { StateDeclaration, _ViewDeclaration, Transition, HookResult } from '@uirouter/core';
                                                                               ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/lazyLoad/lazyLoadNgModule.d.ts:4:62 - error TS2307: Cannot find module '@uirouter/core'.
  
  4 import { Transition, LazyLoadResult, StateDeclaration } from '@uirouter/core';
                                                                 ~~~~~~~~~~~~~~~~m
  node_modules/@uirouter/angular/providers.d.ts:89:129 - error TS2307: Cannot find module '@uirouter/core'.
  
  89 import { UIRouter, StateRegistry, StateService, TransitionService, UrlMatcherFactory, UrlRouter, ViewService, UrlService } from '@uirouter/core';
                                                                                                                                     ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/statebuilders/lazyLoad.d.ts:3:62 - error TS2307: Cannot find module '@uirouter/core'.
  
  3 import { LazyLoadResult, Transition, StateDeclaration } from '@uirouter/core';
                                                                 ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/statebuilders/lazyLoad.d.ts:4:46 - error TS2307: Cannot find module '@uirouter/core'.
  
  4 import { BuilderFunction, StateObject } from '@uirouter/core';
                                                 ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/statebuilders/views.d.ts:2:29 - error TS2307: Cannot find module '@uirouter/core'.
  
  2 import { StateObject } from '@uirouter/core';
                                ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/statebuilders/views.d.ts:3:26 - error TS2307: Cannot find module '@uirouter/core'.
  
  3 import { PathNode } from '@uirouter/core';
                             ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/statebuilders/views.d.ts:4:28 - error TS2307: Cannot find module '@uirouter/core'.
  
  4 import { ViewConfig } from '@uirouter/core';
                               ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/uiRouterConfig.d.ts:2:39 - error TS2307: Cannot find module '@uirouter/core'.
  
  2 import { UIRouter, StateObject } from '@uirouter/core';
                                          ~~~~~~~~~~~~~~~~
  node_modules/@uirouter/angular/uiRouterNgModule.d.ts:6:92 - error TS2307: Cannot find module '@uirouter/core'.
  
  6 import { UrlRuleHandlerFn, TargetState, TargetStateDef, UIRouter, TransitionService } from '@uirouter/core';
                                                                                               ~~~~~~~~~~~~~~~~
  
  ** Angular Live Development Server is listening on localhost:4300, open your browser on http://localhost:4300/ **
  ℹ ｢wdm｣: Failed to compile.
  
  </code></pre>
  
  <p>I suppose the problem is with ui-router, because until I impored the module the console didn't give errors.
  I tried to reinstall the dependencies but it continues to give me that problem that up until a few days ago didn't give me.</p>