libvpx.recipe: Use a tarball instead of git
libvpx.recipe: Use a tarball instead of git

Reduces the download size which speeds up initial builds.

GStreamer/cerbero,GStreamer/cerbero,centricular/cerbero,atsushieno/cerbero,centricular/cerbero,centricular/cerbero,fluendo/cerbero,atsushieno/cerbero,fluendo/cerbero,GStreamer/cerbero,centricular/cerbero,fluendo/cerbero,atsushieno/cerbero,nirbheek/cerbero,nirbheek/cerbero,fluendo/cerbero,nirbheek/cerbero,atsushieno/cerbero,GStreamer/cerbero,GStreamer/cerbero,atsushieno/cerbero,fluendo/cerbero,centricular/cerbero,nirbheek/cerbero