[Bug] README is not correctly shown on verdaccio using `yarn npm publish`

Describe the bug

README is not correctly shown on self-hosted verdaccio using yarn npm publish.

To Reproduce

(require docker to launch verdaccio so as to reproduce)

Reproduction

mkdir yarn-verdaccio-readme
cd yarn-verdaccio-readme
yarn set version berry
echo '
npmPublishRegistry: http://localhost:4873
unsafeHttpWhitelist: [localhost]
' >> .yarnrc.yml
echo '
{
  "name": "yarn-verdaccio-readme",
  "version": "0.1.0"
}
' > package.json
echo '# yarn-verdaccio-readme' > README.md
yarn
docker run --rm -p 4873:4873 -d verdaccio/verdaccio:4.8.1
echo 'input some random username/password'
yarn npm login --publish
yarn npm publish
echo 'open http://localhost:4873/-/web/detail/yarn-verdaccio-readme then you will see "ERROR: No README data found!".'

Screenshots

$ yarn npm publish
➤ YN0000: README.md
➤ YN0000: package.json
➤ YN0000: Package archive published
➤ YN0000: Done in 0.91s

Environment

• Yarn version 2.1.1

Additional context

• README.md is uploaded correctly.
• No issue with npm publish.

[ikatyang]

I found the issue is that the readme field is missing in the publish body:

https://github.com/yarnpkg/berry/blob/bedc0cf6816d5090f812083a9f84fde77584800b/packages/plugin-npm-cli/sources/commands/npm/publish.ts#L164-L199

Adding the readme field can fix the issue:

 return {
+  readme: "# yarn-verdaccio-readme\n",
   _id: name, 
   _attachments: { 

I’m not sure if this should be fixed on the verdaccio side or the yarn side, but I’ll report this to the verdaccio repo as well.

[juanpicado]

Just a small notes from my side, pnpm had the same issue recently on v6 which was fixed a few weeks ago https://github.com/pnpm/pnpm/releases/tag/v6.24.1 https://github.com/pnpm/pnpm/pull/4117 . From verdaccio side, expects the body to contain a readme property with a string of the readme content. Also checking npm8 still sends the readme https://github.com/npm/read-package-json/blob/main/read-json.js#L295