[main] report any errors

src/main/scala/net/kemitix/s3thorp/Main.scala

@@ -1,6 +1,6 @@
 package net.kemitix.s3thorp
 
-import cats.effect.ExitCase.Canceled
+import cats.effect.ExitCase.{Canceled, Completed, Error}
 import cats.effect.{ExitCode, IO, IOApp}
 import cats.syntax.all._
 
@@ -14,7 +14,8 @@ object Main extends IOApp {
   override def run(args: List[String]): IO[ExitCode] =
     exec(args).guaranteeCase {
       case Canceled => IO(println("Interrupted"))
-      case _ => IO(println("Done"))
+      case Error(e) => IO(println("ERROR: " + e))
+      case Completed => IO(println("Done"))
     }
 
 }