Limit Pytest-asyncio to < 0.23.1 (#36037)

Seems that pytest-asyncio 0.23.1 break our asyncio tests. We are
temporarily limiting it until
pytest-dev/pytest-asyncio#703 is
solved or answered.

setup.py

@@ -475,7 +475,9 @@ def write_version(filename: str = str(AIRFLOW_SOURCES_ROOT / "airflow" / "git_ve
     "beautifulsoup4>=4.7.1",
     "coverage>=7.2",
     "pytest>=7.1",
-    "pytest-asyncio",
+    # Pytest-asyncio 0.23.1 breaks our tests. The limitation should be removed when the issue is fixed:
+    # https://github.com/pytest-dev/pytest-asyncio/issues/703
+    "pytest-asyncio<0.23.1",
     "pytest-cov",
     "pytest-httpx",
     "pytest-icdiff",