[FEATURE] Automate release process with goreleaser

[dokwon]

We've been releasing terra core manually; should seek to automate this process via goreleaser.

[etienne-napoleone]

I see that goreleaser had been implemented in #77 but the circleci release step errors as seen in the v0.2.3 job.
My guess is that the GITHUB_TOKEN doesn't have necessary repo access on terra-project/core, thus 404ing when trying to push the files.

Not really easy to debug/try has it only happens during release.
Could it be possible to reissue a token with suffisent access and update the GITHUB_TOKEN env var in the circleci conf?

[hanjukim]

goreleaser has a problem with building binaries. terracli built by goreleaser won't have build tags: netgo ledger enabled. Build tags can be found by running terracli version --long

[dokwon]

Closing; out of scope for columbus-3