Akka.Streams.TestKit 1.4.12

Maintenance Release for Akka.NET 1.4** Akka.NET v1.4.12 is a relatively minor release, but it includes some breaking changes: BREAKING CHANGE**: [Akka.Cluster.Sharding: batch update](https://github.com/akkadotnet/akka.net/pull/4600) - includes some important updates for rebalancing shards more quickly, handling rolling updates, and using the new `AppVersion` type introduced in Akka.NET v1.4.11 to avoid allocating shards onto nodes that are being replaced during an upgrade. The breaking change: renamed the `Akka.Cluster.Sharding.TunningParameters` to `Akka.Cluster.Sharding.TuningParameters` in order to fix a misspelling. This changes the public API of all of the Akka.Cluster.Sharding settings classes - it shouldn't affect your Akka.NET application directly, but it will affect any plugins built on top of Akka.Cluster.Sharding. [Akka.Streams: Make DistinctRetainingFanOutPublisher a public member](https://github.com/akkadotnet/akka.net/pull/4630) - needed to update Akka.Persistence plugins to implement Akka.Persistence.Query "CurrentPersistenceIds` queries correctly. [Introduce Akka.Discovery Module](https://github.com/akkadotnet/akka.net/pull/4599) - introduces the brand new Akka.Discovery module, which allows Akka.NET services to discover Akka.Cluster seed endpoints, Kafka nodes, and more via a variety of methods. This module is still in beta as of 1.4.12 but it will be developed, documented, and incorporated into more tutorials + modules as it matures. You can read more about Akka.Discovery here: https://getakka.net/articles/discovery/index.html To see the [full set of fixes in Akka.NET v1.4.12, please see the milestone on Github](https://github.com/akkadotnet/akka.net/milestone/43). | COMMITS | LOC+ | LOC- | AUTHOR | | --- | --- | --- | --- | | 6 | 333 | 34 | Aaron Stannard | | 2 | 2 | 2 | dependabot-preview[bot] | | 1 | 5 | 25 | Ebere Abanonu | | 1 | 2823 | 384 | zbynek001 | | 1 | 1449 | 0 | Ismael Hamed |