Update vendored module code.gitea.io/git

* GPG commit validation

* Add translation

+ some little fix

* Move hash calc after retrieving of potential key + missing translation

* Add some little test

and updating the vendor directory

- Update import paths from github.com/go-gitea to code.gitea.io
- Fix import path for travis

See https://docs.travis-ci.com/user/languages/go#Go-Import-Path

* Replace gogits/git-module dependency with go-gitea/git

Fixes #92

* Remove git alias for git module import (not needed)