chore(cjs/ems): Re-add CJS for dual module support

[loynoir]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• New feature
• Other, please explain:

What changes did you make? (provide an overview)
Re-add CJS support which dropped in v3.0.0-beta.10.
But ESM & CJS dual module support exists <= v3.0.0-beta.9.

Which issue (if any) does this pull request address?
#1226
#1230

Is there anything you'd like reviewers to know?
ESM & CJS dual module support exists in v3.0.0-beta.9.
As I'm a big fans of ESM, I understand CJS is dropped.
But I don't think it's time to drop CJS support.

PS: As may not re-add CJS, I use esbuild for easy mainteinance.

node-fetch/package.json

Line 9 in 38839c5

"exports": {

node-fetch/package.json

Line 26 in 38839c5

"build": "rollup -c",

node-fetch/rollup.config.js

Line 8 in 38839c5

format: 'cjs',

[jimmywarting]

This is essentially a duplicate variant of PR #1227

[loynoir]

@jimmywarting
Sorry, I did not see that pull, as jest fail, I try to fix that ASAP.
And please consider re-add cjs support, although I'm a big fan of ESM, but that whole ecosystem haven't reached there yet.
So, I think might be better to support both nowadays.

[LinusU]

@loynoir did you read the discussion in #1227? e.g. #1227 (comment)

Feel free to lay out arguments and continue the discussion there ☺️

[jimmywarting]

Locking b/c it's nicer to keep the discussion in one place.
(We still keep a open mind and looking for a solution - it dose not mean we will overlook this PR)

Feel free to keep pushing commits and move the discussion to #1227 where most of the discussion is already happening