code: func ImageFromTemplate(t *template.Template) ImageBuilder {
  	return ImageBuilderFunc(func(ctx context.Context, _ io.Writer, event events.Deployment) (image.Image, error) {
  		buf := new(bytes.Buffer)
  		if err := t.Execute(buf, event); err != nil {
  			return image.Image{}, err
  		}
  
  		return image.Decode(buf.String())
  	})
  }
docs: // ImageFromTemplate returns an ImageBuilder that will execute a template to
  // determine what docker image should be deployed. Note that this doesn't not
  // actually perform any "build".