python: Reformat code with black 22.3.0

swh/core/api/__init__.py

swh/core/api/asynchronous.py

swh/core/api/classes.py

swh/core/api/serializers.py

swh/core/api/tests/server_testing.py

swh/core/api/tests/test_gunicorn.py

swh/core/api/tests/test_rpc_client.py

swh/core/api/tests/test_rpc_server.py

swh/core/api/tests/test_serializers.py

swh/core/cli/__init__.py

swh/core/cli/db.py

swh/core/config.py

swh/core/db/db_utils.py

swh/core/db/pytest_plugin.py

swh/core/db/tests/pytest_plugin/test_pytest_plugin.py

swh/core/db/tests/test_cli.py

swh/core/db/tests/test_db.py

swh/core/db/tests/test_db_utils.py

swh/core/pytest_plugin.py

swh/core/statsd.py