Update links reference under the "Source code and downloads" section

[chinyeungli]

As described in the title, the only changes were to update the links references from https://github.com/nexB/scancode-toolkit to https://github.com/aboutcode-org/scancode-toolkit

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)

The failing tests don't related to the documentation update.

Signed-off-by: Chin Yeung Li [email protected]