By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Point at the released ical-recurrence 0.3.0.0 The previous pin was a commit that no longer exists on any branch: the recurrence work was rebased while being reviewed, so the SHA it named survives only as an unreferenced object. `b6b199c` is the reviewed and merged `master`. `flake.lock` and `stack.yaml` are both updated, because they pin ical independently and nix and stack would otherwise build against different versions of it.