Use free Llama 3 on Groq instead of OpenAI

[jeffxtang]

If using OpenAI is too expensive for you to try out examples with long text, you can create a free API key in seconds at https://console.groq.com/keys using your gmail or github then make the changes below:

1. run:
   pip install groq

2. Add a new line in your .env file (renamed from .env.sample, originally with a line starting with "OPEN_API_KEY"):
   GROQ_API_KEY="your_groq_api_key"

3. In src/translation_agent/utils.py, make 3 changes:

• change import openai to from groq import Groq
• change client = openai.OpenAI(api_key=os.getenv("OPENAI_API_KEY")) to
  client = Groq(api_key=os.getenv("GROQ_API_KEY"))
• change model: str = "gpt-4-turbo" to model: str = "llama3-8b-8192" or model: str = "llama3-70b-8192"

Now running python examples/example_script.py will use Llama 3 on Groq for free.

[icecreamzhao]

Add one more line: change model_name="gpt-4" to model_name="llama3"

[methanet]

@jeffxtang Thanks for the suggestions!
Adding support for Llama would be a great extension to the codebase. Would you like to submit a PR with the proposed extension incorporating the Groq APIs? Much appreciated.

@icecreamzhao good catch!