update svg2pdf to custom version (fix gradient shows up as solid block)

[dippindots]

Fix cBioPortal/cbioportal#6765

Try to update svg2pdf to the latest version, but after updated to the latest version, the jspdf-yworks library throw error (not a constructor), didn't have luck to make it work.
Tried two different ways to solve the issue:

1. Update svg2pdf.js to version from 1.3.3 to 1.3.4, but still use the older jspdf-yworks version. That fixed the fill gradient issue found in oncoprint, but introduced in other issue in study view (some charts will shrink to 1/4).
2. Created a fork of svg2pdf.js library and cherry-pick the commit fixed the issue. Then use that as the package.
   Describe changes proposed in this pull request:

• a fix gradient shows up as solid block
  

[dippindots]

@alisman @adamabeshouse @onursumer Could you comment on this one? I don't think the current solution is good enough, could I get some advices from you? Thanks!

[adamabeshouse]

@dippindots it seems fine to me, why dont you like this solution?

[dippindots]

@adamabeshouse Personally I don't really like to use a specific commit of a package. But I am ok with it, should we at lease make a copy under cbioportal account (the repository using here is under my account)?

[adamabeshouse]

@dippindots that sounds like a good idea. also if you feel better you can make a release and point package.json to that release tag instead of the commit hash

[alisman]

@dippindots yeah, lets put the fork under cbioportal

[dippindots]

@adamabeshouse @alisman Sure, thanks!

[dippindots]

Thanks to @inodb helped me move the svg2pdf.js repo under cbiopotal. @alisman @adamabeshouse @onursumer I updated this pr, could you take a look again? thanks!