fix(package): replaced the http with https version for the api

Author: AnthonyNahas

src/module/service/link-preview.service.spec.ts

@@ -33,7 +33,7 @@ describe('MatLinkPreviewService', () => {
       backend.expectOne((req: HttpRequest<any>) => {
         const params = req.params;
 
-        return req.url === 'http://api.linkpreview.net/'
+        return req.url === 'https://api.linkpreview.net/'
           && req.method === 'GET'
           && params.get('key') === '5b54e80a65c77848ceaa4630331e8384950e09d392365'
           && params.get('q') === 'github.com';

src/module/service/mat-link-preview.service.ts

@@ -10,7 +10,7 @@ import {LinkPreview} from '../..';
 export class MatLinkPreviewService implements OnDestroy {
 
   private _accessKey = '5b54e80a65c77848ceaa4630331e8384950e09d392365';
-  private _apiURL = 'http://api.linkpreview.net/';
+  private _apiURL = 'https://api.linkpreview.net/';
   private _subscription: Subscription;
 
   onLinkFound: EventEmitter<Array<Link>> = new EventEmitter<Array<Link>>();