chore: fix Buffer deprecation warning in test

[Gelio]

There was a deprecation warning because new Buffer([]) was used in one of the tests.

(node:25795) [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)
 PASS  __tests__/manual.js

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[mweststrate]

Thanks!

[mweststrate]

🎉 This PR is included in version 8.0.1 🎉

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