Uses deprecated `new Buffer()` which gives warning

[buckett]

Description

When running anything that makes requests to the API a warning is emitted on newer versions of nodejs:

(node:41042) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.
(Use `node --trace-deprecation ...` to show where the warning was created)

This is because the code uses the new Buffer(string) method which is deprecated and since version 10 has emitted this warning: https://nodejs.org/api/buffer.html#new-bufferstring-encoding