Avoid running goreleaser on (tagged) PRs #45
Description
goreleaser runs on PRs and fails due to PRs internal merge commit being different from the PRs branch HEAD commit:
Instead, it should only run on tags, and we should push these tags to the stable branch.
Running goreleaser on PRs probably has extra value, as it checks that the code compiles. So, let's consider adding some other checks for PRs.