return __anext__ for all python versions above 2

Author: Bilal Al

splitio/optional/loaders.py

@@ -17,5 +17,7 @@ def missing_asyncio_dependencies(*_, **__):
 async def _anext(it):
     return await it.__anext__()
 
-if sys.version_info.major < 3 or sys.version_info.minor < 10:
-    anext = _anext
+if sys.version_info.major > 2:
+    anext = _anext
+else:
+    anext = "Asyncio is not supported"