upgrade puppet to 1.6 and Dockerfile node version

[mkirank]

No description provided.

[marcellerusu]

Is there a reason to move to node 10.x? 10 is not LTS yet unless I'm misreading the chart https://github.com/nodejs/Release#release-schedule

[VojtechVitek]

LGTM

Is node:10.6 preferred by Puppeteer project itself?

[marcellerusu]

https://github.com/GoogleChrome/puppeteer/blob/master/package.json#L8

puppeteer seems to support back to 6.4 but doesn't say anything (I can find) about preferences, I assume they stick with the current LTS version.

[VojtechVitek]

Yeah, they still use https://github.com/GoogleChrome/puppeteer/blob/master/docs/troubleshooting.md.

But I'm fine with updating to a newer version, if everything works OK. We're in Docker world, I'm not really worried that it's not a LTS.