Update to 1.8.0

Changelog: https://blog.gitea.io/2019/04/gitea-1.8.0-is-released/

PR: 237734
Submitted by: stb@lassitu.de (maintainer)
Approved by: ports-secteam (joneum)
Security: a1de4ae9-6fda-11e9-9ba0-4c72b94353b5
Sponsored by: Netzkommune GmbH