Beautify skeleton loader on coursebook list

aleksis/apps/alsijil/frontend/components/coursebook/CourseBookList.vue

@@ -17,11 +17,9 @@
     >
       <v-card
         class="flex-grow-1"
-        v-for="idx in 4"
-        :key="idx"
       >
         <v-skeleton-loader
-          type="heading, text@2, actions"
+          type="article, actions"
         ></v-skeleton-loader>
       </v-card>
     </v-col>