Add support for Python 3.11, stop support of Python 3.4 and 3.5

[szerepak]

• Adjust the asyncio syntax to Python 3.11
• Remove support for Python 3.4 and 3.5

Unit tests results:

platform darwin -- Python 3.6.15, pytest-7.0.1, pluggy-1.0.0
plugins: asyncio-0.16.0, mock-3.6.1, cov-4.0.0
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]

platform darwin -- Python 3.7.16, pytest-7.2.1, pluggy-1.0.0
plugins: asyncio-0.20.3, mock-3.10.0, cov-4.0.0
asyncio: mode=strict
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]

platform darwin -- Python 3.8.16, pytest-7.2.1, pluggy-1.0.0
plugins: asyncio-0.20.3, mock-3.10.0, cov-4.0.0
asyncio: mode=strict
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]

platform darwin -- Python 3.9.6, pytest-7.2.1, pluggy-1.0.0
plugins: asyncio-0.20.3, mock-3.10.0, cov-4.0.0
asyncio: mode=strict
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]

platform darwin -- Python 3.10.2, pytest-7.2.0, pluggy-1.0.0
plugins: asyncio-0.20.3, mock-3.10.0, cov-4.0.0
asyncio: mode=strict
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]

platform darwin -- Python 3.11.1, pytest-7.2.1, pluggy-1.0.0
plugins: asyncio-0.20.3, mock-3.10.0, cov-4.0.0
asyncio: mode=Mode.STRICT
collected 28 items                                                                                                                     

tests/test_general.py ..........                                                                                                 [ 35%]
tests/test_queue.py ..........                                                                                                   [ 71%]
tests/test_transport.py ........                                                                                                 [100%]