buffer construction uses deprecated methods

[matthewleon]

quoting https://nodejs.org/api/buffer.html#buffer_buffer

To make the creation of Buffer instances more reliable and less error prone, the various forms of the new Buffer() constructor have been deprecated and replaced by separate Buffer.from(), Buffer.alloc(), and Buffer.allocUnsafe() methods.

Developers should migrate all existing uses of the new Buffer() constructors to one of these new APIs.

[hdgarrood]

Thanks for the report! This was fixed by #31.