Gopkg.toml,github: update rest dependency

This removes a lot of the imports that the rest package previously
depended on that we actually don't need.

Fixes github-release#110.

github: strip querystring from returned URL

Previously we would leak credentials to error logs.

Fixes github-release#85.

github-release v0.8.1

New Docker-based release procedure.

github-release v0.8.0

github-release 0.7.2

github-release 0.7.1

github-release 0.7.0

github-release 0.6.4

github-release 0.6.3

github-release 0.6.2