upgrade and migrate

src/app/pages/account/voucher/voucher.component.html

@@ -3,9 +3,9 @@
         <p>{{'vouchers.info' | i18n}}</p>
     </mat-card-content>
     <mat-card-actions>
-        <button *ngFor="let name of available" mat-raised-button  (click)="create(name)" matTooltip="{{'vouchers.' + name  + '.text' | i18n}}">
+        <a *ngFor="let name of available" mat-raised-button  (click)="create(name)" matTooltip="{{'vouchers.' + name  + '.text' | i18n}}">
             {{'vouchers.' + name | i18n}}
-        </button>
+        </a>
     </mat-card-actions>
     <mat-card-footer>
         <a href="https://wiki.bstly.de/services/webstly#voucher" class="help-button" matTooltip="{{'help-button' | i18n}}"

src/app/pages/account/voucher/voucher.dialog.html

@@ -8,5 +8,5 @@
         {{'vouchers.stored-safely.confirm' | i18n}}
     </mat-slide-toggle>
 
-    <button mat-button (click)="onOkClick()" [disabled]="!data.confirmClose">{{'ok' | i18n}}</button>
+    <a mat-button (click)="onOkClick()" [disabled]="!data.confirmClose">{{'ok' | i18n}}</a>
 </div>