Update Serialport Dependency

[aelmiger]

I think this module cannot be installed with the current node v13.5 due to compile issues of @serialport/bindings (v.2.0.8). The older serialport version is not compatible with the newer node version.
This can be fixed be raising the serialport dependency to version 8.

[williamcolbert]

I ran into the same problem

Created a pull request #21

[williamcolbert]

Closed the pull request for now looks like more needs to be done to get it to work with the lastest node and serialport.

[codefoster]

Thanks, all. I haven't looked at this project in a while, but I'll put it on my short list to do so.

[transistormuncher]

Hi @codefoster , any chance you might have a look at this over the holidays? I would love to use your program, but cannot install it due to the issues mentioned above. Thank you!