fix(genapi): Adding dependencies requirements for MacOS and Debian/Ubuntu

Adding dependencies requirements for MacOS and Debian/Ubuntu, and fixing python packages version.

Author: fpagny

tutorials/how-to-implement-rag-generativeapis/index.mdx

@@ -34,16 +34,31 @@ In this tutorial, you will learn how to implement RAG using LangChain, a leading
 
 ### Install required packages
 
-Run the following command to install the required Python packages:
+#### MacOS
+Run the following command to install the required MacOS packages to analyze PDF files and connect to PostgreSQL using Python:
+
+   ```sh
+   brew install libmagic poppler tesseract qpdf libpq python3-dev
+   ```
+
+#### Debian/Ubuntu
+Run the following command to install the required Debian/Ubuntu packages to analyze PDF files and connect to PostgreSQL using Python:
+
+   ```sh
+   sudo apt-get install libmagic-dev tesseract-ocr poppler-utils qpdf libpq-dev python3-dev build-essential python3-opencv
+   ```
+
+#### All OS
+Once you have installed prerequisites for your OS, run the following command to install the required Python packages:
 
    ```sh
    pip install langchain langchainhub langchain_openai langchain_community langchain_postgres unstructured "unstructured[pdf]" libmagic python-dotenv psycopg2 boto3
    ```
 
-   If you are on MacOS, run also the following command to install dependencies required by the `unstructured` package:
+   This command will install the latest version for all packages. If you want to limit dependencies conflicts risks, you can install the following specific versions instead:
 
    ```sh
-   brew install libmagic poppler tesseract qpdf
+   pip install langchain==0.3.9 langchainhub==0.1.21 langchain-openai==0.2.10 langchain-community==0.3.8 langchain-postgres==0.0.12 unstructured==0.16.8 "unstructured[pdf]" libmagic==1.0 python-dotenv==1.0.1 psycopg2==2.9.10 boto3==1.35.71
    ```
 
 ### Create a .env file