Update XML file for clickable PDF

[prosimplecoding]

All links added

[adam-golab]

Could you provide some instructions about how you added links in draw.io? So that everyone will know how to edit the file in case of adding new libraries to the roadmap?
Also, I have a problem with importing the XML file from your branch in draw.io. I'm getting an error about Unescaped '<'. Could you fix it?

[prosimplecoding]

@adam-golab Yes, I will write instruction to README file.

To import XML file to draw.io:

1. Download archive file from my patch-1 branch into your device.
2. Extract file react-developer-roadmap.xml from archive.
3. Open draw.io, then: File -> Open from -> Device....
4. Choose extracted XML file (react-developer-roadmap.xml) and click to "Open".

In my opinion, import from GitHub is not working well.

I checked XML file in xmlvalidation.com. No errors found.

[adam-golab]

I meant instruction about editing the roadmap in draw.io. How to add links and export it to PDF.

[prosimplecoding]

@adam-golab ok, I understood.

[prosimplecoding]

@adam-golab fixed problem with importing . More on #35