fixed description of --output

Signed-off-by: Andreas Ulm <andreas.ulm@root360.de>

cmd/flags.go

@@ -35,7 +35,7 @@ var RepoFlag = cli.StringFlag{
 // OutputFlag provides flag to specify output type
 var OutputFlag = cli.StringFlag{
 	Name:        "output, o",
-	Usage:       "Indicate one repository, optional when inside a gitea repository",
+	Usage:       "Specify output format. (csv, simple, table, tsv, yaml)",
 	Destination: &outputValue,
 }