add pricing information for gpt4o

[marcklingen]

Discussed in https://github.com/orgs/langfuse/discussions/2045

^{Originally posted by varenc May 13, 2024}

Describe the feature or potential improvement

OpenAI released their gpt-4o model today and it's now immediately available to all API users. It make sense for Langfuse to include this as one of the official pre-filled models. The docs say to request official support via an issue like this.

Additional information

There's both a gpt-4o and a gpt-4o-2024-05-13 per the usual convention. Also I believe langfuse will need to update to the latest version 7.0 of tiktoken which was just updated with gpt-4o support.

Here's a screenshot of the working a model definition I create for myself:

But note: in the model's openai Tokenizer config I had to just claim the model was the older gpt-4-turbo. Setting { ..., "tokenizerModel":"gpt-4o-2024-05-13", ... } resulted in gpt-4o logs showing 0 tokens, hence the need for a tiktoken upgraded.