Release v0.6

[benjaminjkraft]

It's been a few months; not that much is new but when we get a chance we should release a new version. Probably can be 0.5.1 since there's not that much in it. 0.6 since it includes the Go version bump.

[benjaminjkraft]

@csilvers or @dnerdy I'm guessing you've pulled e322738/#241 in at Khan? Once you have we can call that commit tested and I'll cut the release when I get a chance (maybe not for a few weeks though depending how busy I end up).

[csilvers]

Actually we haven't had a chance to make use of it yet. I just wanted to get started on the genqlient part early since I know it can take time to cut a new release.

[benjaminjkraft]

#269