feat(publish): support "publishConfig.directory" field

[PabloSzx]

Adding support for "publishConfig.directory" field, feature present in changesets changesets/changesets#428, and lerna: https://github.com/lerna/lerna/tree/main/commands/publish#publishconfigdirectory

[zkochan]

Please add a test

[PabloSzx]

@zkochan I facing an issue, I was able to test this feature, and it works by looking at the logs (since npm execution stdio is being inherited), but I'm not able to spy that stdout programmatically, I did a search online and I couldn't find anything about inspecting an stdio inherit process

[zkochan]

after publishing the package, install it and check the contents. There are similar tests already in the project.

[PabloSzx]

@zkochan I tried following some of the other tests doing the install and I wasn't able to make it work, I give up 😢, the feature is certainly doing it's job, the package in the publishConfig.directory is being published as it can be seen in the logs

[PabloSzx]

While testing this feature in v6.7.0 I realized there is something wrong, the cwd is set correctly, but not the npm publish arg 😢

This is weird, because in the tests everything worked as intended 🤔