Use valid Plotly.js CDN

[ndrezn]

The plotly-latest CDN in use in this project is unfortunately deprecated: https://github.com/plotly/plotly_matlab/blob/7007414824c7df5f782f025bf902cf072fbd3f06/plotlysetup_offline.m#L14

This should be updated to the latest (or at least pinned to a version plotly_matlab supports) -- see e.g. https://plotly.com/javascript/getting-started/

The format looks like: https://cdn.plot.ly/plotly-3.2.0.min.js