v4.0.0

Usage related changelog:

• Breaking change: This library no longer works with CJS. It is ESM only.
• Removed logRequestOptions. Replaced it with debug instead.
• Added returnError option.

Dev related changelog:

• Rewrote all tests in Vitest
• Tests are now all robust and no need for manual testing!
• Removed need for btoa dependency
• Removed need for cross-fetch dependency
• Now uses node-fetch underneath the hood for Node

v3.4.0...v4.0.0