GitLab

* Update IFEval dataset to official one

This PR updates the IFEval dataset to the one hosted under the Google org: https://huggingface.co/datasets/google/IFEval

Note the main change is an updated prompt from this commit in the GitHub repo: https://github.com/google-research/google-research/commit/26d8ccdab6fec61b5c83ad6327ea8bda9e580288



* Update ifeval.yaml

---------
Co-authored-by: Hailey Schoelkopf <65563625+haileyschoelkopf@users.noreply.github.com>

* fix incorrect lookback protections

* bump generate_until task versions

* change version field formatting in metadata

* mention versioning in new task guide

* add instructions for changelog

* run linters

* Add IFEval task

* Check and download nltk punkt if not already downloaded

* Update gen_max_toks to 2048 to support "900 words+" instructions

* Resolve pre-commit linting issues

* Reduce max_gen_toks to 1280 to conserve token usage

* Add warning message in `process_results` call for non chat-finetuned models