deps: upgrade npm to 6.4.0

[zkat]

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Where this should land

• Node 10
• Node 8

Notable Changes

This release includes two versions of npm, including the current latest release, npm@6.4.0.

• f861c2b57 node-gyp@3.8.0: This means our entire npm dep tree now uses the latest node-gyp, and we've updated and flattened request as well. npm audit on npm itself comes up clean now! (@rvagg)

• 6e9f04b0b npm/cli#8 Search for authentication token defined by environment variables by preventing the translation layer from env variable to npm option from breaking :_authToken. (@mkhl)

• 84bfd23e7 npm/cli#35 Stop filtering out non-IPv4 addresses from local-addrs, making npm actually use IPv6 addresses when it must. (@valentin2105)

• d81146181 npm/cli#32 Don't check for updates to npm when we are updating npm itself. (@olore)

• Another reminder that we've moved our issue tracking! You can read more about our move away from GitHub for issue tracking on our blog

Changelogs

• 6.3.0-next.0
• 6.3.0
• 6.4.0

[brody4hire]

I would like to thank @zkat, @rvagg, and others for the dedication behind this nice update. I suspect you already know that we will have to wait a couple weeks for this one to land ref:

• https://github.com/nodejs/node/blob/master/doc/guides/maintaining-npm.md
• OpenSSL Releases 14th August 2018 #22187 (comment)

[zkat]

Yes, I'm aware of the policy, seeing as I was part of the discussion for it. :)

[BridgeAR]

RSLGTM

[BridgeAR]

CI https://ci.nodejs.org/job/node-test-pull-request/16516/
CI-NPM https://ci.nodejs.org/view/All/job/node-test-npm/36/
CI-NPM-WIN https://ci.nodejs.org/view/All/job/node-test-npm-win/11/

[joyeecheung]

This PR needs a rebase against master to avoid the git failure in the CI.

[BridgeAR]

@joyeecheung would it not be sufficient to rebase on the CI task?

[zkat]

I've rebased it 👍

[zkat]

Moving this to #22591, since 6.4.1 came out in the meantime 😅

[brody4hire]

Doesn't that mean we have to wait another 2 weeks to get npm@6.4.x integrated?