Updated packet.js

[tionsys]

Constructor of Buffer is now deprecated
See https://nodejs.org/api/buffer.html#buffer_new_buffer_size

[glaszig]

Buffer.alloc has been introduced in 5.10 which would change the nodejs requirement. i'm ok with that. i would even up the requirement to node lts. but is there anything else that'd need changes?

[tionsys]

In my setup it does work like a charm - I copied most parts of my script and modified them working as a standalone example; but I wasn't able to test it (yet) and won't be able to do so in the next days.
Also updated package.json.