Update go-serial to build for darwin

[dehanj]

Due to stricter enforcement of rules in Go 1.21, go-serial version < 1.6.0 does not build on darwin.
So for our applications to be supported on darwin for Go 1.21, go-serial needs to be updated to at > 1.6.0, see release notes here.

# go.bug.st/serial/enumerator
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:142:11: cannot define new methods on non-local type C.CFStringRef
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:148:11: cannot define new methods on non-local type C.CFTypeRef
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:154:11: cannot define new methods on non-local type *C.io_registry_entry_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:165:11: cannot define new methods on non-local type *C.io_registry_entry_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:175:11: cannot define new methods on non-local type *C.io_registry_entry_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:194:11: cannot define new methods on non-local type *C.io_registry_entry_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:214:11: cannot define new methods on non-local type *C.io_iterator_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:218:11: cannot define new methods on non-local type *C.io_iterator_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:222:11: cannot define new methods on non-local type *C.io_iterator_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:229:11: cannot define new methods on non-local type *C.io_object_t
../../../go/pkg/mod/go.bug.st/[email protected]/enumerator/usb_darwin.go:233:11: cannot define new methods on non-local type *C.io_object_t

[dehanj]

close with #105

[stefanb]

This still needs to be released so that it can be built with Go 1.22:

• go 1.22.0 Homebrew/homebrew-core#157782

[dehanj]

This still needs to be released so that it can be built with Go 1.22:

* [go 1.22rc1 Homebrew/homebrew-core#157782](https://github.com/Homebrew/homebrew-core/pull/157782)

Correct, we have a few more things we want to include before release.