chore: update version to 0.4.0-dev and add unreleased section in changelog

Author: yifanfeng97

hyperdb/__init__.py

@@ -2,6 +2,6 @@
 from .base import BaseHypergraphDB  # noqa: F401
 from .hypergraph import HypergraphDB  # noqa: F401
 
-__version__ = "0.3.0"
+__version__ = "0.4.0-dev"
 
 __all__ = ["AUTHOR_EMAIL", "BaseHypergraphDB", "HypergraphDB"]

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "hypergraph-db"
-version = "0.3.0"
+version = "0.4.0-dev"
 description = "A Lightweight Hypergraph Database with hypergraph visualization."
 authors = [
     {name = "Yifan Feng", email = "[email protected]"}