Update index.yml to use https://aka.ms/ArcJumpstart/

Update index.yml to use https://aka.ms/ArcJumpstart/

Author: thomasmaurer

articles/azure-arc/index.yml

@@ -26,7 +26,7 @@ highlightedContent:
     # Card
     - title: Azure Arc Jumpstart
       itemType: sample
-      url: https://aka.ms/AzureArcJumpstart/
+      url: https://aka.ms/ArcJumpstart/
       # Card
     - title: Azure Arc-enabled servers
       itemType: overview