Replace Google Drive with GitHub release assets

Google Drive has caused some problems when hosting assets. It has
blocked downloads when detecting them as viruses, and hit download
limits.

GitHub has different policies:

    At this time, we do not place any limits on the size of binary
    uploads nor the bandwidth used to deliver them.

Via https://help.github.com/articles/distributing-large-binaries
tag-build: end developer changelog with shortlog

The shortlog is a superset of the author list, and should remove the
pressure for the prose section to summarize all changes.