Aiobotocore

^^^^^^^^^^^^^^^^^^
* put backwards incompatible changes behind ``AIOBOTOCORE_DEPRECATED_1_4_0_APIS`` env var. This means that `876 <https://github.com/aio-libs/aiobotocore/issues/876>`_ will not work unless this env var has been set to 0.

^^^^^^^^^^^^^^^^^^
* fix retries via config `877 <https://github.com/aio-libs/aiobotocore/pull/877>`_
* remove AioSession and get_session top level names to match botocore_
* change exceptions raised to match those of botocore_, see `mappings <https://github.com/aio-libs/aiobotocore/pull/877/files#diff-b1675e1eb4276bfae81107cda919ba446e4ce1b1e228a9e878d65dd1f474bf8cR162-R181>`_

^^^^^^^^^^^^^^^^^^
* fix AioJSONParser `872 <https://github.com/aio-libs/aiobotocore/issues/872>`_

^^^^^^^^^^^^^^^^^^
* Bump to botocore_ to `1.20.106 <https://github.com/boto/botocore/tree/1.20.106>`_

^^^^^^^^^^^^^^^^^^
* TCPConnector: change deprecated ssl_context to ssl
* fix non awaited generate presigned url calls `868 <https://github.com/aio-libs/aiobotocore/issues/868>`_

^^^^^^^^^^^^^^^^^^
* Bump to botocore_ to `1.20.49 <https://github.com/boto/botocore/tree/1.20.49>`_ `#856 <https://github.com/aio-libs/aiobotocore/pull/856>`_