Define external D3 library gone wrong : Uncaught SyntaxError: Unexpected token '<'

[lenaig]

Hello,

I am trying to develop an extension on Qlik Sense with a D3.js library that I found on Github.

I tried to import it that way (line 4) 

When I tried to launch my extension on Qlik Sense Desktop, this is what I got : 

And the error seems to come from the import inside the d3-simple-gauge lib right here at the top of the file:

And I know for a fact that the lib is working. 
I tried so many different things that didn't help to move forward from these error.

Did someone had the same issue ?
Thank you !