(all): update removal in deprecation warnings from 0.2 to 0.3 (#21265)

We are pushing out the removal of these to 0.3.

`find . -type f -name "*.py" -exec sed -i ''
's/removal="0\.2/removal="0.3/g' {} +`

libs/community/langchain_community/vectorstores/astradb.py

@@ -67,7 +67,7 @@ def _unique_list(lst: List[T], key: Callable[[T], U]) -> List[T]:
 
 @deprecated(
     since="0.0.21",
-    removal="0.2.0",
+    removal="0.3.0",
     alternative_import="langchain_astradb.AstraDBVectorStore",
 )
 class AstraDB(VectorStore):