Allow configuring plotly.js

[alyst]

Currently PlotlyBase.jl uses plotly.js 2.3.0 (also it's the version that plotly-base-artifacts provides), which is almost two years old and does not support some nice features, e.g. shape labels.

Technically, in the current PlotlyBase.jl the plotly.js version is specified in PLOTLYJS_VERSION constant.
This PR turns into into a configurable variable, that could be read/set with PlotlyBase.plotly_version() and PlotlyBase.set_plotly_version() calls, respectively.
The PR also updates the used plotly.js version to 2.33.0.

[alyst]

@sglyon Could you please take a look?

[hhaensel]

Maybe, one should also adapt the deps to produce a more modern artifact?

I just bumped the plotlyjs version in our StipplePlotly package in order to take advantage of the latest plotly features, e.g. alignment in sankey plots.

So doing the same here is certainly a good idea. Before releasing, one could bump the version to today's latest version.

[hhaensel]

Hi @sglyon ,
I think @alyst 's PR merits your consideration. Being able to set the required plotly version is a superb feature, particularly as the first release candidate of version 3.0.0 is out.
I recommend applying this PR and changing the version to the current v2.35.2.
As already commented above, plotly.js has made some advances in the past two years that should be part of PlotlyJS.

To me the alignment of sankey plots was a major breakthrough for one of my apps, where I had to fiddle with manual alignment before - and it was never error-free.

[hhaensel]

Also PR #107 is absolutely valid and well done from my perspective.

[sglyon]

Thank you both!

[disberd]

Thanks @alyst for this which is a very nice contribution!

@sglyon, I see there have been a bunch of nice PR merged recently, do you have in mind to tag a new PlotlyBase release soon so that all downstream packages can benefit from these?

[hhaensel]

If you do so, please also consider PR #110 ;-)
However, of all the PRs certainly the least important one.