Move to ESM

[SerLizar]

The upstream module has been changed to ESM only. Since you said that your intention was:

I want to keep this module being an exactly-same-but-reversed copy of camelcase-keys

This module should be updated to be ESM only too.

[sindresorhus]

The package name was transferred to me (I'm the author of camelcase-keys), and this was done in: https://github.com/sindresorhus/decamelize-keys

[SerLizar]

Excellent!

That should be added to the read me of this repo for maximum visibility.