version upgrade for upcoming release

pyproject.toml

 [tool.poetry]
 name = "semantic-router"
-version = "0.0.20"
+version = "0.0.21"
 description = "Super fast semantic router for AI decision making"
 authors = [
     "James Briggs <james@aurelio.ai>",

semantic_router/__init__.py

@@ -4,4 +4,4 @@ from semantic_router.route import Route
 
 __all__ = ["RouteLayer", "HybridRouteLayer", "Route", "LayerConfig"]
 
-__version__ = "0.0.20"
+__version__ = "0.0.21"