updates to readme

Author: patr-amazon

README.md

@@ -31,3 +31,4 @@ Below is an outline of the workshop content:
 * **Module 1: Advanced Prompt Engineering for Text-to-SQL.** Use Amazon Bedrock to implement some of the State-of-the-Art techniques against an Amazon Athena data set and a relational database.
 * **Module 2: Retrieval Augmented Generation (RAG) for Text-to-SQL.** Leverage a FAISS in-memory vector store of data set meta data to improve query accuracy.
 * **Module 3: Fine-tuning for Text-to-SQL.** Fine-tune a Titan model on the Spider Dataset to improve Text-to-SQL accuracy.
+* **Module 4: Introduction to Security for Text-to-SQL.** Guard against prompt injection and SQL injection using these prompt engineering techniques.