update black to 21.6b0 (#10197)

changelog.d/10197.misc

contrib/experiments/cursesio.py

setup.py

synapse/handlers/federation.py

synapse/http/servlet.py

synapse/replication/tcp/handler.py

synapse/types.py

tests/handlers/test_appservice.py

tests/handlers/test_directory.py

tests/handlers/test_profile.py

tests/handlers/test_register.py

tests/handlers/test_sync.py

tests/rest/client/v1/test_events.py

tests/rest/client/v1/test_presence.py

tests/rest/client/v1/test_rooms.py

tests/rest/client/v1/test_typing.py

tests/storage/test_base.py