Upgrading the UWP gstreamer binaries

1. download the appropriate x64/arm64 tarballs (both -devel and not) from https://nirbheek.in/files/binaries/gstreamer/1.17.1/2020-06-18/
2. obtain the installed directories (use The Unarchiver on macOS)
3. make a new gstreamer-uwp-[version] directory, and make x64 and arm64 directories inside it
4. move the contents of gstreamer-1.0-uwp-arm64-[version] into gstreamer-uwp-[version]/arm64
5. move the contents of gstreamer-1.0-uwp-x64-[version] into gstreamer-uwp-[version]/x64
6. move the contents of the subdirectories of gstreamer-1.0-uwp-arm64-[version]-devel into the corresponding subdirectories of gstreamer-uwp-[version]/arm64
7. move the contents of the subdirectories of gstreamer-1.0-uwp-x64-[version]-devel into the corresponding subdirectories of gstreamer-uwp-[version]/x64
8. zip -r gstreamer-uwp-[version].zip gstreamer-uwp-[version]
9. s3put -b servo-deps --prefix $(pwd) --key_prefix msvc-deps/ --grant public-read gstreamer-uwp-[version].zip (requires the boto pip package)
10. update this line to reflect the new version