Include $DOCS_ANALYTICS when building docs

[phillipj]

Subsystem: docs

I'm following up #6601 which enables Google Analytics tracking on docs pages.

For the tracking code to be included, $DOCS_ANALYTICS needs to be set when running make doc. I've been having trouble finding who or where docs are generated when a new release is made, so I don't really know who to ping.

Found the Node.js release guide wiki page which has a section named Publish API docs, but it seems outdated the website-upload make target doesn't exist anymore.

[evanlucas]

@phillipj We currently follow https://github.com/nodejs/node/blob/master/doc/releases.md when cutting releases. I'm pretty sure there is some magic on in ci-release that actually pushes the api docs though. /cc @rvagg or @jbergstroem?

[phillipj]

@mikeal what should the Google Analytics ID be for docs?

[phillipj]

@mikeal please confirm the GA ID UA-67020396-1.

Found it in your initial shot a GA trackings in docs (#6462), which also looks to be the same as we use on www.nodejs.org.

[phillipj]

@rvagg are docs generated somewhere in CI when cutting releases?

[phillipj]

@rvagg ping ^

[phillipj]

Closing this for now as @rvagg just added $DOCS_ANALYTICS as requested.

Refs nodejs/nodejs.org#1268 (comment)