MQTTnet 5.0.1.1416

**! Read the migration guide (https://github.com/dotnet/MQTTnet/wiki/Upgrading-guide) before migrating to version 5!** ## Changes * Memory usage optimizations (thanks to @mregen) * Performance optimizations (thanks to @mregen) * Removal of no longer supported .NET Frameworks **(BREAKING CHANGE)** * Changed code signing and nuget certificate * Namespace changes **(BREAKING CHANGE)** * Removal of Managed Client **(BREAKING CHANGE)** * Fixed missing release notes in nuget packages. * Client: MQTT 5.0.0 is now the default version when connecting with a server **(BREAKING CHANGE)** * Client: Fixed enhanced authentication. * Client: Exposed WebSocket compression options in MQTT client options (thanks to @victornor, #2127) * Client: Fixed wrong timeout for keep alive check (thanks to @Erw1nT, #2129) * Server: Fixed enhanced authentication. * Server: Set default for "MaxPendingMessagesPerClient" to 1000 **(BREAKING CHANGE)** * Server: Set SSL version to "None" which will let the OS choose the version **(BREAKING CHANGE)** * Server: Added API for getting a single session (thanks to @AntonSmolkov, #2131) * Server: Fixed "TryPrivate" (Mosquitto feature) handling (thanks to @victornor, #2125) **(BREAKING CHANGE)** * Server: Fixed dead lock when awaiting a packet transmission but the packet gets dropped due to quotas (#2117, thanks to @AntonSmolkov)