message: ci: correctly rebase PRs for branches contain a slash (/)
  Previously, due to a bug in `rebase-pr.js`, PRs for branches containing
  a slash (/) in their name would fail to be rebased
  ([example failure][1]).
  This commit ensures that such branch names are handled correctly.
  [1]:
  PR Close
diff: @@ -92,7 +92,7 @@ async function _main() {
  * likely correct branch will be the first one encountered in the list.
  */
  function getRefFromBranchList(gitOutput) {
  - const branches = gitOutput.split('\n').map(b => b.split('/').slice(1).join('').trim());
  + const branches = gitOutput.split('\n').map(b => b.split('/').slice(1).join('/').trim());
  return branches.sort((a, b) => {
  if (a === 'master') {
  return -1;
  