Proposal: use publint to validate package exports

[yudai-nkt]

To avoid bugs like #819 in future development, I'd like to propose using publint, which checks validity of exports field in package.json. I believe this is useful when adding a new exports entry and refactoring existing ones because Hono has many of those. You can try publint in the v3.0.0-rc.7 tag to see what kind of errors it reports:

$ git checkout v3.0.0-rc.7
$ yarn build
$ npx publint
hono lint results:
Errors:
1. pkg.exports["./cloudflare-pages"].types is ./dist/types/adapter/cloudflare-pages/index.d.ts but file does not exist.
2. pkg.exports["./cloudflare-pages"].import is ./dist/adapter/cloudflare-pages/index.js but file does not exist.
3. pkg.exports["./cloudflare-pages"].require is ./dist/cjs/adapter/cloudflare-pages/index.js but file does not exist.

If this is accepted, I'm going to submit a PR based on my publint branch. What do you think @yusukebe?

[yusukebe]

Hi @yudai-nkt !

That's great!! I was struggling with a problem that was only known after it was released to the public. I really want to use "publint". Let's go with it!

[yudai-nkt]

Done at #824!