Changes from the latest stable gnuton build:
- build: circleci builds release from tags and build pre-releases for each change in dsl-unstable
- build: do not build mainline branch and fix yaml parsing
- build: Use SNAPSHOT as TAG for CI pre-releases
- build: changelog file is generated from log during build job
- build: removed description for pre-release
- build: circleci: tag and dir must be the last arguments of ghr
- build: circleci: publish-github-ci-pre-release runs only when commits are tagged with snapshot
- build: circleci: tag only filter was not working
- build: circleci: snapshots are built for tags gnuton-snapshot.*
- Pre-release runs only for tags
- build: circleci: Changelogs are created from git logs for releases and pre-releases. Added pre-releases support
- build: circleci: fixed regexp in order to match versions with underscore