fix(publish) Pass only the project scope to libnpmpublish

[armandocanals]

Description

Parse the @scope from the full package name using npm-package-arg and set projectScope.

The projectScope parameter is used by libnpmpublish to set the HTTP_NPM_SCOPE header.

Motivation and Context

When publishing scoped packages with Lerna, the projectScope used by libnpmpublish was being set using the full package name (@scope/name).

This behavior caused some third-party registries to fail when verifying the HTTP_NPM_SCOPE header which was expected to match the package @scope.

How Has This Been Tested?

These changes have been tested against the official npm registry and third-party registries to ensure that only the @scope parameter will go through libnpmpublish as the projectScope.

Updated tests in npm-publish.test to include @scope.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Related issue

Fixes #1968

[armandocanals]

Seems like CI is only failing for Node v11.11.0 which might be related to this: jestjs/jest#8069

[evocateur]

Thanks!