Fix flux install command so it returns an error when unexpected arguments are passed

Co-authored-by: Max Jonas Werner <makkes@users.noreply.github.com>
Signed-off-by: Vinícius Garcia <vingarcia00@gmail.com>

cmd/flux/install.go

@@ -36,6 +36,7 @@ import (
 
 var installCmd = &cobra.Command{
 	Use:   "install",
+	Args:  cobra.NoArgs,
 	Short: "Install or upgrade Flux",
 	Long: `The install command deploys Flux in the specified namespace.
 If a previous version is installed, then an in-place upgrade will be performed.`,