code: func (s *RepositoriesService) GetCommit(ctx context.Context, owner, repo, sha string) (*RepositoryCommit, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/commits/%v", owner, repo, sha)
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	commit := new(RepositoryCommit)
  	resp, err := s.client.Do(ctx, req, commit)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return commit, resp, nil
  }
docs: // GetCommit fetches the specified commit, including all details about it.
  //
  // GitHub API docs: https://developer.github.com/v3/repos/commits/#get-a-single-commit
  // See also: https://developer.github.com/v3/git/commits/#get-a-single-commit provides the same functionality