Types needs to be updated for ESM

[sindresorhus]

https://github.com/jaredwray/cacheable-request/blob/main/src/types.ts

You cannot use namespace. Use named exports instead of nesting in a namespace.

I don't have time to work on this, but if you mention me on a pull request, I'm happy to review it to ensure everything is correct.

[alphmt]

@jaredwray @sindresorhus can you review PR?

[jaredwray]

@alphmth and @sindresorhus - reviewed and merged.