code: func (s *GitService) GetBlobRaw(ctx context.Context, owner, repo, sha string) ([]byte, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/git/blobs/%v", owner, repo, sha)
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  	req.Header.Set("Accept", "application/vnd.github.v3.raw")
  
  	var buf bytes.Buffer
  	resp, err := s.client.Do(ctx, req, &buf)
  	return buf.Bytes(), resp, err
  }
docs: // GetBlobRaw fetches a blob's contents from a repo.
  // Unlike GetBlob, it returns the raw bytes rather than the base64-encoded data.
  //
  // GitHub API docs: https://developer.github.com/v3/git/blobs/#get-a-blob