FR: Upgrade to plotly.js 1.50.0

Hi, 
A soon upgrade to the  just released plotly.js 1.50.0 would be much appreciated.

Especially this fix could solve some issues we have in our shiny app (other users might experience the same?):
- Fix numerous axis `automargin` bugs [#4165, #4216]

I just tried to upgrde myself by replacing the plotly.min.js but wasn't successful myself.