fix(demo): updated angular material to v8

Author: AnthonyNahas

demo/package-lock.json

@@ -17,13 +17,13 @@
   "dependencies": {
     "@angular-material-extensions/faq": "^3.0.4",
     "@angular/animations": "^8.1.3",
-    "@angular/cdk": "^6.4.7",
+    "@angular/cdk": "^8.1.2",
     "@angular/common": "^8.1.3",
     "@angular/compiler": "^8.1.3",
     "@angular/core": "^8.1.3",
     "@angular/flex-layout": "^6.0.0-beta.18",
     "@angular/forms": "^8.1.3",
-    "@angular/material": "^6.4.7",
+    "@angular/material": "^8.1.2",
     "@angular/platform-browser": "^8.1.3",
     "@angular/platform-browser-dynamic": "^8.1.3",
     "@angular/platform-server": "^8.1.3",

demo/package.json

@@ -3,7 +3,10 @@ import {CommonModule} from '@angular/common';
 import {MatJumbotronModule} from '@angular-material-extensions/jumbotron';
 import {HomeRoutingModule} from './home-routing.module';
 import {HomeComponent} from './home.component';
-import {MatButtonModule, MatCardModule, MatIconModule, MatTabsModule} from '@angular/material';
+import { MatButtonModule } from '@angular/material/button';
+import { MatCardModule } from '@angular/material/card';
+import { MatIconModule } from '@angular/material/icon';
+import { MatTabsModule } from '@angular/material/tabs';
 import {FlexLayoutModule} from '@angular/flex-layout';
 import {HighlightModule} from 'ngx-highlightjs';