Updating flip icon

frontend/src/app/components/blockchain/blockchain.component.html

@@ -6,7 +6,7 @@
         <app-blockchain-blocks></app-blockchain-blocks>
       </div>
       <div id="divider">
-        <button class="time-toggle" (click)="toggleTimeDirection()"><fa-icon [icon]="['fas', 'arrows-rotate']" [fixedWidth]="true"></fa-icon></button>
+        <button class="time-toggle" (click)="toggleTimeDirection()"><fa-icon [icon]="['fas', 'exchange-alt']" [fixedWidth]="true"></fa-icon></button>
       </div>
     </span>
   </div>