Description

Attempting to publish to GitHub Packages yields a 405 error - it appears that the step which checks for package name availability is unable to run against the registry.

Steps to reproduce

1. Add https://npm.pkg.github.com/ to publishConfig in package.json.
2. Run NODE_ENV=test np

Expected behavior

Publish should be successful.

Environment

np - 5.2.1
Node.js - 10.17.0
npm - 6.11.3
Git - 2.21.0
OS - macOS Catalina 10.15.1