Update README setup example: anthropic:claude-3-5-sonnet-20240620 is deprecated

[autosoda]

The setup example in the README currently uses anthropic:claude-3-5-sonnet-20240620. However, this specific version has been deprecated by Anthropic and lead to API errors for users attempting to run the example.

import aisuite as ai
from dotenv import load_dotenv

load_dotenv()

client = ai.Client()

# This model version is deprecated
models = ["openai:gpt-4o", "anthropic:claude-3-5-sonnet-20240620"]

messages = [
    {"role": "system", "content": "Respond in Pirate English."},
    {"role": "user", "content": "Tell me a joke."},
]

for model in models:
    response = client.chat.completions.create(
        model=model, messages=messages, temperature=0.75
    )
    print(response.choices[0].message.content)

(entry) PS C:\Users\k123k\Desktop\entry> & c:/Users/k123k/Desktop/entry/.venv/Scripts/python.exe c:/Users/k123k/Desktop/entry/src/entry/__init__.py
Why did the pirate go to school? To improve his arrrrrrrt skills! Arrr!
Traceback (most recent call last):
  File "c:\Users\k123k\Desktop\entry\src\entry\__init__.py", line 16, in <module>
    response = client.chat.completions.create(
        model=model, messages=messages, temperature=0.75
    )
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\aisuite\client.py", line 355, in create
    response = provider.chat_completions_create(model_name, messages, **kwargs)
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\aisuite\providers\anthropic_provider.py", line 229, in chat_completions_create
    response = self.client.messages.create(
        model=model, system=system_message, messages=converted_messages, **kwargs
    )
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\anthropic\_utils\_utils.py", line 277, in wrapper  
    return func(*args, **kwargs)
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\anthropic\resources\messages.py", line 904, in create
    return self._post(
           ~~~~~~~~~~^
        "/v1/messages",
        ^^^^^^^^^^^^^^^
    ...<22 lines>...
        stream_cls=Stream[RawMessageStreamEvent],
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\anthropic\_base_client.py", line 1249, in post     
    return cast(ResponseT, self.request(cast_to, opts, stream=stream, stream_cls=stream_cls))
                           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\anthropic\_base_client.py", line 931, in request   
    return self._request(
           ~~~~~~~~~~~~~^
        cast_to=cast_to,
        ^^^^^^^^^^^^^^^^
    ...<3 lines>...
        remaining_retries=remaining_retries,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "C:\Users\k123k\Desktop\entry\.venv\Lib\site-packages\anthropic\_base_client.py", line 1029, in _request 
    raise self._make_status_error_from_response(err.response) from None
anthropic.NotFoundError: Error code: 404 - {'type': 'error', 'error': {'type': 'not_found_error', 'message': 'model: claude-3-5-sonnet-20240620'}, 'request_id': 'req_011CWCUwaxFVrW3RnrF8Y9jV'}