Update ReadMe with New Cookbook link

Author: royziv11

README.md

@@ -68,6 +68,7 @@ We suggest getting starting by:
 - Walking through the process for building an eval: [`build-eval.md`](docs/build-eval.md)
 - Exploring an example of implementing custom eval logic: [`custom-eval.md`](docs/custom-eval.md)
 - Writing your own completion functions: [`completion-fns.md`](docs/completion-fns.md)
+- Review our starter guide for writing evals: [Getting Started with OpenAI Evals](https://cookbook.openai.com/examples/evaluation/getting_started_with_openai_evals)
 
 Please note that we are currently not accepting evals with custom code! While we ask you to not submit such evals at the moment, you can still submit model-graded evals with custom model-graded YAML files.