Release langchain==0.2.4

Changes since langchain==0.2.3

langchain: release 0.2.4 (#22872)
ci: add testing with Python 3.12 (#22813)
langchain[minor]: Make EmbeddingsFilters async (#22737)
langchain[minor]: Add native async implementation to LLMFilter, add concurrency to both sync and async paths (#22739)
langchain[patch]: allow to use partial variables in create_sql_query_chain (#22688)
community[patch]: fix WandbTracer to work with new "RunV2" API (#22673)
langchain[minor]: Add pgvector to list of supported vectorstores in self query retriever (#22678)