Corrected yarn version on node 10 and 13

[GrahamCampbell]

This change was made for node 12, but forgotten for 10 and 13.

[SimenB]

We only update the yarn version on new releases of node that are not security releases.

Node 13 will be updated when 13.9.0 are available on Alpine (possibly blocked by nodejs/node#31858) and 10 will be updated whenever 10 has a new release.

See https://github.com/nodejs/docker-node/blob/master/CONTRIBUTING.md#version-updates and https://github.com/nodejs/docker-node/blob/master/docs/BestPractices.md#upgradingdowngrading-yarn for how to upgrade yourself if you want to

[GrahamCampbell]

Hopefully, there will be at least one more release of node 10, otherwise you will never put yarn 1.22 in the image?

[GrahamCampbell]

They are scheduled to go into maintenance only in April 2020, so hopefully they will decide to do a release with some new stuff before then.

[SimenB]

Node 10 will be supported so long as it's not EOL (which is slated for April 2021), so I assume we'll update at some point before that. But we don't want to change the version (unless it's a security release) within an existing version of node.

[GrahamCampbell]

The problem was:

We only update the yarn version on new releases of node that are not security releases.

Between April 2020 and 2021, the only node 10 releases will be security releases.