Release v0.11.0

A new reactor catches up from the very beginning of the event sequence, and reactors.OnceOnly() does not stop that. A reactor whose handlers cause side effects can now opt out of history with reactors.StartAtTail().

Added

• reactors.StartAtTail() option. The first time Chronicle sees the reactor, it begins at the tail of the event sequence and observes only what is appended afterwards. A reactor that already has a position keeps it, and an explicit replay still replays from the beginning. See https://github.com/Cratis/Chronicle.Go/blob/main/Documentation/reactors.md#skipping-history-on-first-registration. (part of Cratis/Direct#1875)
• Generated contracts for the new Chronicle occurrences service.

Changed

• Contracts and the verified decision-guard profile move to Chronicle 19.70.0. Run a Chronicle server of 19.70.0 or later: an older server ignores reactors.StartAtTail() and the reactor catches up from the beginning, and decision guards are only supported against the verified 19.70.0 profile.