Update yarn to v0.23.4

[PeterDaveHello]

No description provided.

[pesho]

Please take a look at the discussion starting at #386 (comment)

We should probably stick to updating Yarn only together with new Node releases.

[chorrell]

So I guess we can close this for #389 since it already has the yarn update along with the Node.js updates for v4 and v6

[chorrell]

Actually never mind. I see #389 was already updated to remove the yarn updates

[pesho]

Actually never mind. I see #389 was already updated to remove the yarn updates

However, the current PR also updates Yarn in branches which have no new release.

[chorrell]

Oh, well, crap.

I'll do a PR that reverts the change for v7.

[chorrell]

See #391

If I can get a quick approval I'll merge. I can do the Docker Hub PR but if someone else wants to take that on that would be great.

[pesho]

I can do the Docker Hub PR but if someone else wants to take that on that would be great.

@chorrell no problem, I'll handle it.

[pesho]

Upstream PR: docker-library/official-images#2919

[razor-x]

I was really hoping yarn 0.24.x would make it in time for node 6.10.3. Keep in mind I like keeping the yarn version relatively stable in each node release, but the original issue I had that brought that up was because yarn was updated from 0.22.0 to 0.23.x which broke things: 0.24.x contains fixes to regressions I've been waiting on.

Anyway, if 0.23.x is going to be in node 6.10.3 and I have to wait another month or so for yarn 0.24.x, then I would really appreciate seeing at least #381 merged in to fix the 6.10.3 image (and all the other images that use yarn < 0.24.x which would be affected).

That is the last major regression I'm dealing with and it should IMO be patched in the images which will never get the fix from the newer yarn versions.