doc: add link to CoC
readdir-scoped-modules@1.0.1

Ensures the hegemony of `graceful-fs` over all fs operations, thus
helping to address #6506. Probably not the whole solution to the
problem.
npm-registry-client@4.0.3

Send GitHub the JSON accepts header it's looking for when we request a
tarball via an HTML redirect page. The internet is terrible.

Fixes #6729.
Fixes #6735 - "already built" is not error

initial change and test
fix typo warn=>info
factor test setup
small grammar fix
tweaks to test
Fix leak into global scope