Broken links to examples of (beta) releases

[albert-github]

In the documentation output of the 6.0. beta1 we have links:

• in doc_output/Manual/usage.html to https://github.com/CGAL/cgal/releases/download/v6.0/CGAL-6.0-examples.tar.xz
• in doc_output/Manual/windows.html to https://github.com/CGAL/cgal/releases/download/v6.0/CGAL-6.0-examples.zip

These links don't exist as the release is called:

https://github.com/CGAL/cgal/releases/tag/v6.0-beta1

and the file names contain also beta1 in it.

I think it should be considered to add the beta1 to these links as well .
Looks like it is currently steered (in the documentation through the command \cgalReleaseNumber that again is defined as ALIASES += "cgalReleaseNumber=${CGAL_DOC_VERSION}"