conjugate gradients and CGLS.
*   Added gradients for `matrix_solve_ls` and `self_adjoint_eig`.
*   Large cleanup to add second order gradient for ops with C++ gradients and
    improve existing gradients such that most ops can now be differentiated
    multiple times.
*   Added a solver for ordinary differential equations,
    `tf.contrib.integrate.odeint`.

  const resp = await github.rest.issues.create({
    owner,
    repo,
    assignees: assignee_logins,
    title: `Issue created for Rollback of PR #${pr_number}: ${pr_title}`,
    body: `Merged PR #${pr_number} is rolled back in ${rollback_commit}.
    Please follow up with the reviewer and close this issue once its resolved.`
  });
  return `Issue created: ${resp.data.number} with Title: ${resp.data.title}`;