There was a mix of diferent action and Go versions specified throughout the
GitHub Actions workflow configs. In general, we want to be compatible with the
latest Go 1.x version, so just specify that instead of bumping versions
everywhere when necessary.
At the same time, bump the actions/setup-go to v4, the latest currently
available version. This prefers versions already cached on the runner and
enables automatic caching for dependencies.
If I remember correctly, some time ago you were able to download artifacts from
the job page, i.e. there was no issues with two jobs using the same artifact
name within one workflow. Now it looks like you can only download the artifacts
from the workflow page, so this commit allows you to download both files from
there.
