Update tutorial-java-quarkus-postgresql-app.md

fixes MicrosoftDocs/azure-docs#101031

Author: RyanHill-MSFT

articles/app-service/tutorial-java-quarkus-postgresql-app.md

@@ -102,8 +102,8 @@ Follow these steps to create an Azure PostgreSQL database in your subscription.
         --resource-group $RESOURCE_GROUP \
         --name $DB_SERVER_NAME \
         --location $LOCATION \
-        --admin-user $DB_USERNAME \
-        --admin-password $DB_PASSWORD \
+        --admin-user $ADMIN_USERNAME \
+        --admin-password $ADMIN_PASSWORD \
         --sku-name GP_Gen5_2
     ```