reorg test structure to match tox and CI jobs, drop bumpversion for bump-my-version and move config to pyproject.toml, fix docs building

tests/core/stream_muxer/conftest.py

@@ -0,0 +1,24 @@
+import pytest
+
+from libp2p.tools.factories import (
+    mplex_conn_pair_factory,
+    mplex_stream_pair_factory,
+)
+
+
+@pytest.fixture
+async def mplex_conn_pair(security_protocol):
+    async with mplex_conn_pair_factory(
+        security_protocol=security_protocol
+    ) as mplex_conn_pair:
+        assert mplex_conn_pair[0].is_initiator
+        assert not mplex_conn_pair[1].is_initiator
+        yield mplex_conn_pair[0], mplex_conn_pair[1]
+
+
+@pytest.fixture
+async def mplex_stream_pair(security_protocol):
+    async with mplex_stream_pair_factory(
+        security_protocol=security_protocol
+    ) as mplex_stream_pair:
+        yield mplex_stream_pair