fix waitgroup instantiation

main.go

@@ -86,7 +86,7 @@ func refreshData() {
 	}
 	lastRefresh = time.Now()
 
-	var wg *sync.WaitGroup
+	wg := sync.WaitGroup{}
 
 	// Loop through each configured account provider and attempt to get the account balances, and update YNAB
 	for _, p := range configuredProviders {