fix: update python pyproject.toml version to 4.0.6

Author: sunli829

python/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "longbridge"
-version = "4.0.5"
+version = "4.0.6"
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Intended Audience :: Developers",