message: Make "Update release branch" workflow fail if `npm version` fails
diff: @@ -88,6 +88,7 @@ def open_pr(
  body.append('')
  body.append('Please review the following:')
  if len(conflicted_files) > 0:
  + body.append('- The package.json file contains the correct version.')
  body.append(' - [ ] You have added commits to this branch that resolve the merge conflicts ' +
  'in the following files:')
  body.extend([f' - [ ] `{file}`' for file in conflicted_files])
  @@ -296,15 +297,15 @@ def main():
  # Migrate the package version number from a v2 version number to a v1 version number
  print(f'Setting version number to {version}')
  - subprocess.run(['npm', 'version', version, '--no-git-tag-version'])
  + subprocess.check_output(['npm', 'version', version, '--no-git-tag-version'])
  run_git('add', 'package.json', 'package-lock.json')
  # Migrate the changelog notes from v2 version numbers to v1 version numbers
  print('Migrating changelog notes from v2 to v1')
  - subprocess.run(['sed', '-i', 's/^## 2\./## 1./g', 'CHANGELOG.md'])
  + subprocess.check_output(['sed', '-i', 's/^## 2\./## 1./g', 'CHANGELOG.md'])
  # Remove changelog notes from v2 that don't apply to v1
  - subprocess.run(['sed', '-i', '/^- \[v2+ only\]/d', 'CHANGELOG.md'])
  + subprocess.check_output(['sed', '-i', '/^- \[v2+ only\]/d', 'CHANGELOG.md'])
  # Amend the commit generated by `npm version` to update the CHANGELOG
  run_git('add', 'CHANGELOG.md')
  