Add github action to test goreleaser config

[dergeberl]

This PR pins the version for goreleaser and adds a config check. So we get information about deprecated config options early. Renovate will bump the goreleaser version in the actions.

Additionally it builds the release without publish (--snapshot)

    --snapshot             Generate an unversioned snapshot release, skipping all validations and without publishing any artifacts (implies --skip=announce,publish,validate)

This PR also addresses the already deprecated fields.