docs: added another angular example

showcase/angular-lts-minus-1-showcase/src/app/components/form/form.component.html

@@ -29,7 +29,7 @@
         <db-select
           label="Selectbox"
           name="select-name"
-          [formControl]="selectControl"
+          (dbChange)="onFormChange($event)"
         >
           <option selected>Option 1</option>
           <option>Option 2</option>

showcase/angular-lts-minus-1-showcase/src/app/components/form/form.component.ts

@@ -44,4 +44,8 @@ export class FormComponent implements OnInit {
       })
     );
   }
+
+  onFormChange = (event: any) => {
+    this.select = event.target.value;
+  };
 }