Downgrades puppeteer to ~1.11.0

[KaiVolland]

This downgrades puppeteer to version ~1.11.0.

Version 1.11.x will download the stable version of chromium (72.0.3582.0), while version 1.12.x downloads the beta version of chromium (73.0.3679.0).

Fixes #9288

[marcjansen]

This looks like the right change atm. we should carefully watch when greenkeeper wants to update this again.

[ahocevar]

Sorry for being late to the party, but I think the issue we were seeing here with Chromium 74 is something that's there to stay, and the issue will come up again when Chromium 74 is on the stable channel. This is also why I'm not opposed to use the dev version for running tests, because it helps us catch problems before the majority of users gets exposed to them.

Floating point arithmetics can always cause issues like this, so maybe doing a toFixed(Math.abs(exponent)) after Math.pow(base, exponent) for numbers lower than 1 with a negative exponent in the ScaleLine code would be appropriate?

[marcjansen]

Fine for me, @KaiVolland can probably come up with a PR that addresses this. Thanks for the input.