chore: bump version to 0.4.0 (#32)

- Update version from 0.3.0 to 0.4.0
- Includes performance optimization for _index_query method

Author: yuanoOo

oceanbase-sqlalchemy-plugin/setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name="oceanbase-sqlalchemy",
-    version="0.3.0",
+    version="0.4.0",
     description="SQLAlchemy dialect for OceanBase Oracle mode (supports SQLAlchemy 1.3.x and 2.0+)",
     long_description=open("README.md", "r", encoding="utf-8").read(),
     long_description_content_type="text/markdown",