Remove entries from "publishConfig" when publishing.

[hyrious]

• I'd be willing to implement this feature (contributing guide)

Describe the user story

Fields in package.json will be edited as publishConfig specified, I hope it can also delete those field when they are "used" since they are no longer meaningful.

Describe the solution you'd like

for (const key of PUBLISH_CONFIG_WHITELIST) {
  if (key in publishConfig) {
    pkg[key] = publishConfig[key]
    delete publishConfig[key]
  }
}
if (Object.keys(publishConfig[key]).length === 0) {
  delete pkg.publishConfig
}

Describe the drawbacks of your solution

What if someone need a field to exist at two places (both in top level and in publishConfig)? I haven't seen the meaning of this behavior.

Describe alternatives you've considered

Make it possible to apply a custom hook function to the package.json when publishing.