chore(examples): reference main prop in README.md in Firebase example

[AaronJY]

Added a reference to the main property within package.json under "The crucial files for the setup:" heading.

[balazsorban44]

I am not sure I understand this:

https://github.com/AaronJY/next.js/blob/d2ee0f7227aa3b259dbae2530efa53612be52747/examples/with-firebase-hosting/package.json#L2

Here is the docs for the private property: https://docs.npmjs.com/cli/v9/configuring-npm/package-json#private

Could you explain a bit more about what this PR does?

[AaronJY]

I am not sure I understand this:

https://github.com/AaronJY/next.js/blob/d2ee0f7227aa3b259dbae2530efa53612be52747/examples/with-firebase-hosting/package.json#L2

Here is the docs for the private property: https://docs.npmjs.com/cli/v9/configuring-npm/package-json#private

Could you explain a bit more about what this PR does?

Sorry @balazsorban44, this was a really poor PR! It was quite late when I raised this and meant to type main instead of private. I've updated the README.md file to mention that the main property in package.json is important as it needs to point to firebaseFunctions.js for everything to work, and there isn't a reference to this in the docs yet.

I've updated the PR to fix the typo.