Describe the bug

Listing extensions/addons is broken on Windows.

To Reproduce

Open GRASS on Windows (tested with https://grass.osgeo.org/grass80/binary/mswindows/native/WinGRASS-8.0.0-1-Setup.exe) and type:

g.extension -l
ERROR: Download file from <https://grass.osgeo.org/addons/grass8/modules.xml>, failed. File is not on the server or check your internet connection.

But https://grass.osgeo.org/addons/grass8/modules.xml exists...

BTW, 8.0.0RC2 worked without any problem...

Expected behavior

List of extensions/addons printed out :-)

Screenshots

System description (please complete the following information):

• Operating System: Windows
• GRASS GIS version 8.0.0