📖 Document problems with rights as a non-root user.

[matchcom-cahors]

The plugin did not work for me at first.
After I tried to control the beamer manually with GTKTerm, I noticed that the corresponding rights for accessing /dev/ttyUSB0 were missing. (I use an Ubuntu with the user ubuntu and not root on my Homebridge server). After I changed the file access rights with "sudo chmod 777 /dev/ttyUSB0" it worked without problems. The rights can of course be specified more precisely and not so freely that everyone has access.

It would be great if this could be mentioned in the documentation for beginners who are not familiar with serial connections under Linux.

Great plugin thanks for the development.