* Update GolangCI-lint and lint config
The `algo` parameter for the `unparam` linter has been removed and we
should thus no longer specify it. Also, bumping the GolangCI-lint
version to the latest available minor release.
See: mvdan/unparam@e6a6d1c51b
* Fix and improve bintray CI script
* Further CI setup improvements
* Split-out CI steps into stand-alone scripts