Versions 2.17.0 to 2.18.1 (since change to webpack), window.d3 is defined to the Plotly packaged D3 3.8.0 version. This prevents loading a newer version of D3.
A newer version is needed since Plotly 2.0.0 to access d3.csv/json and also d3 colours (eg d3.schemeCategory10)
Workaround is to set window.d3 = undefined after loading Plotly.js and then including external D3