Fix docker container setup for goreleaser

[MichaelEischer]

What is the purpose of this change? What does it change?

The expected approach is that the binary built by goreleaser is added to the docker container.

Was the change discussed in an issue or in the forum before?

The container on the docker hub is not yet version 0.12.0

Checklist

• [x] I have enabled maintainer edits for this PR
• [ ] I have added tests for all changes in this PR
• [ ] I have added documentation for the changes (in the manual)
• [ ] There's a new file in changelog/unreleased/ that describes the changes for our users (template here)
• [x] I have run gofmt on the code in all commits
• [x] All commit messages are formatted in the same style as the other commits in the repo
• [x] I'm done, this Pull Request is ready for review