Fix(stdin-handler): Scanln instead of scanf

cmd/messenger/main.go

@@ -44,7 +44,7 @@ func main() {
 func handleStdIn(webhookFlag *bool, webhookURL *string) {
 	for {
 		var currStr string
-		_, err := fmt.Scanf("%s", &currStr)
+		_, err := fmt.Scanln(&currStr)
 		if err != nil {
 			return
 		}