LedgerCosmos.CheckVersion error on unsupported version should display the Ledger major version for a better user experience

[odeke-em]

This switch

ledger-cosmos-go/user_app.go

Lines 84 to 90 in e9d4c19

	switch version.Major {
	case 1:
	return CheckVersion(ver, VersionInfo{0, 1, 5, 1})
	case 2:
	return CheckVersion(ver, VersionInfo{0, 2, 1, 0})
	default:
	return errors.New("App version is not supported")

sends back an error without context but really we should make it return the Ledger's major version so

Suggestion

 default: 
 	return fmt.Errorf("Ledger device version: %d is not supported", version.Major)

/cc @elias-orijtech @julienrbrt

[odeke-em]

Same thing for

ledger-cosmos-go/user_app.go

Lines 126 to 127 in e9d4c19

	default:
	return nil, errors.New("App version is not supported")