This rewrites the release logic to use CircleCI 2.0 and its approve workflow in combination with the state of the release notes to determine what to do next.
Fixes#3779
As pointed out by the linter, some exported functions and types are
missing doc comments.
The linter warnings have been reduced from 194 to 116.
Not all missing comments have been added in this commit though.
This commit adds a work flow aroung GoReleaser to get the Hugo release process automated and more uniform:
* It can be run fully automated or in two steps to allow for manual edits of the relase notes.
* It supports both patch and full releases.
* It fetches author, issue, repo info. etc. for the release notes from GitHub.
* The file names produced are mainly the same as before, but we no use tar.gz as archive for all Unix versions.
* There isn't a fully automated CI setup in place yet, but the release tag is marked in the commit message with "[ci deploy]"
Fixes#3358
