Release a 0.32.1 bugfix pinning to last known working OpenAI release

Installing LLM right now gives a broken build because the new OpenAI 3.x version no longer depends on `httpx`. I'll fix that properly in 0.32 but for the moment let's get a 0.32.1 release out that pins to the older OpenAI version. (I was going to use add `httpx` but the tests would all still fail, so this is a more robust short-term fix.)