Amodbus

-----------------
- Python 3.9 is reaching end of life, and no longer supported.
Depending on the usage the code might still work

-----------------

-------------
* Allow id=0 and check if response.id == request.id. (2572)

-------------
* New simulator is WIP, not to be used. (2568)
* dev_id=0 no response expected (returns ExceptionResponse(0xff)). (2567)
* New simulator datastore. (2535)

-------------
* Parameterize string encoding in convert_to_registers and convert_from_registers (2558)
* Fix client modbus function calls in remote by adding count as keyword argument (2563)
* Fix exception text in ModbusPDU.validateAddress (2551)
* Typo arround `no_response_expected` (2550)
* Trace new connection in server. (2549)
* Add trace to server.
* Update misleading DATATYPE text. (2547)
* Fix pylint.
* Clarify server usage.
* Solve instable transaction testing. (2538)

-------------
* Remove deprecate from payload. (2532)
* Add background parameter to servers. (2529)
* Split async_io.py and simplify server start/stop. (2528)
* Update custom_msg example to include server. (2527)
* Move repl doc to repl repo. (2522)
* Add API to set max until disconnect. (2521)

-------------
* Asyncio future removed from sync client. (2514)