doc,meta: reduce npm PR wait period to one week

The two-week wait period for merging npm releases is one of those rule
exceptions that would be great to get rid of (in my opinion at least).
There are too many exceptions to our rules and they tend to be scattered
across multiple documents. People don't feel confident they know the
rules, thus hampering both project velocity and Collaborator confidence.
It also means I (and perhaps others?) get lots of pings about whether
this or that can land, etc.

This particular issue has come up a few times lately, and is
specifically calling for an exception-to-the-exception so that the
latest version of npm can be released along with Node.js 13.0.0.
Refs: nodejs#29885 (comment)

I propose here reducing the wait period from two weeks to one week. If,
after some amount of time, there seems to be no problems caused by this
change, we can consider further reducing the wait period to 48 hours to
align it with all other change requests. Even if you think that is going
too far, hopefully we can at least get it reduced to a week, as the
second week of the waiting period is usually just the PR sitting around
with an occasional ping from someone about whether/when it can land.

PR-URL: nodejs#29922
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

doc/guides/maintaining-npm.md

@@ -4,7 +4,7 @@ New pull requests should be opened when a "next" version of npm has
 been released. Once the "next" version has been promoted to "latest"
 the PR should be updated as necessary.
 
-Two weeks after the "latest" release has been promoted it can land on master
+One week after the "latest" release has been promoted, it can land on master
 assuming no major regressions are found. There are no additional constraints
 for Semver-Major releases.