please update pdf.js to 4.x or 3.x

[chenbingbcb]

please update, thank you very much!

[Archie3d]

I will take a look, but if you are able to help with this please submit a pull request, otherwise it may take me a while.

[chenbingbcb]

I will take a look, but if you are able to help with this please submit a pull request, otherwise it may take me a while.

it seems that creating a pull request is failure. i just forked(look at https://github.com/chenbingbcb/qpdf) and tried, but it did not work.