code: func (t *Template) WithArtifact(a artifact.Artifact, replacements map[string]string) *Template {
  	var bin = a.Extra[binary]
  	if bin == nil {
  		bin = t.fields[projectName]
  	}
  	t.fields[os] = replace(replacements, a.Goos)
  	t.fields[arch] = replace(replacements, a.Goarch)
  	t.fields[arm] = replace(replacements, a.Goarm)
  	t.fields[binary] = bin.(string)
  	t.fields[artifactName] = a.Name
  	return t
  }
docs: // WithArtifact populates fields from the artifact and replacements