news: reflect upgrade to zstd 1.3.8
news: reflect upgrade to zstd 1.3.8

The initial porting is now complete. Builds work. Tests pass.

Next up is exposing things under new names.

indygreg/python-zstandard,indygreg/python-zstandard,indygreg/python-zstandard,indygreg/python-zstandard