bump to 0.6.4a1

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "reflex"
-version = "0.6.4dev1"
+version = "0.6.4a1"
 description = "Web apps in pure Python."
 license = "Apache-2.0"
 authors = [
@@ -104,4 +104,4 @@ lint.pydocstyle.convention = "google"
 
 [tool.pytest.ini_options]
 asyncio_default_fixture_loop_scope = "function"
-asyncio_mode = "auto"
+asyncio_mode = "auto"