doc: request default snap track be updated for LTS

Ref: nodejs/snap#4

doc/guides/releases.md

@@ -896,9 +896,20 @@ test, or doc-related are to be listed as notable changes. Some SEMVER-MINOR
 commits may be listed as notable changes on a case-by-case basis. Use your
 judgment there.
 
+### Snap
+
+The Node.js [Snap][] package has a "default" for installs where the user hasn't
+specified a release line ("track" in Snap terminology). This should be updated
+to point to the most recently activated LTS. A member of the Node.js Build
+Infrastructure team is able to perform the switch of the default. An issue
+should be opened on the [Node.js Snap management repository][] requesting this
+take place once a new LTS line has been released.
+
 [Build issue tracker]: https://github.com/nodejs/build/issues/new
 [CI lockdown procedure]: https://github.com/nodejs/build/blob/HEAD/doc/jenkins-guide.md#restricting-access-for-security-releases
+[Node.js Snap management repository]: https://github.com/nodejs/snap
 [Partner Communities]: https://github.com/nodejs/community-committee/blob/HEAD/governance/PARTNER_COMMUNITIES.md
+[Snap]: https://snapcraft.io/node
 [nodejs.org release-post.js script]: https://github.com/nodejs/nodejs.org/blob/HEAD/scripts/release-post.js
 [nodejs.org repository]: https://github.com/nodejs/nodejs.org
 [webchat.freenode.net]: https://webchat.freenode.net/