Release langchain-anthropic==0.1.18

Changes since langchain-anthropic==0.1.17

anthropic[patch]: release 0.1.18 (#23778)
anthropic[patch]: fix model name in some integration tests (#23779)
anthropic[patch]: tool output parser fix (#23647)
anthropic[patch]: use core output parsers for structured output (#23776)
langchain_anthropic: add stop_reason in ChatAnthropic stream result (#23689)
standard-tests[patch]: add anthropic format integration test (#23717)