Release v19.4.5

Added

• CHRONICLE_MONGODB_IMAGE selects the MongoDB image the integration fixtures start. Current MongoDB refuses to start on some host kernels, and the refusal surfaces as a container start timeout that explains nothing, leaving integration scenarios unrunnable on that machine.

Fixed

• A projection whose children use a constant parent key now applies every event to them, not just the ones that create them. Previously, when the root carried event types of its own, later events for an existing child were dropped: a fixed-key document counting things kept an accurate root total while updates and removals to its children went nowhere, so a count of what was still open kept counting things that had closed. Creations still landed, so the document looked healthy. (#4105)
• A projection can now combine a root-level constant key with constant-parent-key children in one read model. It previously failed to resolve the child's parent, forcing the total and the membership set into separate read models. (#4099)