Convert @primer/react to ESM, don't generate CommonJS bundle.

[radglob]

Changed some configuration files to use .cjs extension, others to use .mjs extension, and remove settings to produce CommonJS bundle.

There are likely a lot more changes we could make (ex. only using import instead of require in some places) but this seems to produce an ESM bundle and continues to work correctly in a toy project.

Closes#2108.

Screenshots

Please provide before/after screenshots for any visual changes

Merge checklist

• Added/updated tests
• Added/updated documentation
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge

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[changeset-bot]

🦋 Changeset detected

Latest commit: 4b752b0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/react	Major

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[github-actions]

size-limit report 📦

Path	Size
dist/browser.esm.js	98.51 KB (+0.03% 🔺)
dist/browser.umd.js	99.08 KB (+0.04% 🔺)

[joshblack]

Looking great! Just left a comment for the package.json file itself 👀

[joshblack]

@radglob just wanted to double check, I'm still not seeing "type": "module" in package.json and was curious if it's on my end or if it still needs to be added 👀

[radglob]

@radglob just wanted to double check, I'm still not seeing "type": "module" in package.json and was curious if it's on my end or if it still needs to be added 👀

Yeah, that was a mistake on my part. I think I got distracted changing up the exports.

[joshblack]

Closing this out due to the technical limitations mentioned in: #3565 😞 Will make sure to use this as the base for any follow-up ESM work 🤞