fix: Empty commit to re-trigger release process

GitHub Actions failed late during the release process, leading to an
incomplete release. See:

https://github.com/twpayne/chezmoi/actions/runs/21051646274/job/60539608417
https://github.com/twpayne/chezmoi/actions/runs/21051985389/job/60540653385

It looks like GitHub Actions detected the v2.69.2 tag twice and
triggered the release action twice. The first run was canceled by GitHub
Actions, just after it uploaded the immutable GitHub Release. The second
run failed because the immutable release already existed.

Author: twpayne