use one feedz source for both libvlc and libvlcsharp preview packages

Use one feed for all platforms libvlc preview builds

fixes WACK

[skip ci]

see the one from VLC

Binaries taken from this build https://code.videolan.org/videolan/vlc-winrt/pipelines/10590
The ones from 3.0.8 release were deleted from the CI (not kept for ever),
the 3.x libvlc branch is faily stable,
vlc-winrt does not get many updates,
and 3.0.9 is coming up,

so I took the liberty to push this build.

Fixes videolan/LibVLCSharp#241

Previous one went offline

Since most of the libvlc repositories have sort of their own tags and release cycles, this file will help track what fix is released on which platform.