Revert "Bump rector/rector dependency to ^2.3.1"

[DerManoMann]

Reverts #1914

[github-actions]

Backport failed for 5.x, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin 5.x
git worktree add -d .worktree/backport-1915-to-5.x origin/5.x
cd .worktree/backport-1915-to-5.x
git switch --create backport-1915-to-5.x
git cherry-pick -x 5266730a2e5ba40430069dd9972ede2ec0b021a4