feat(bedrock): Temporary AWS credentials via env vars + supported models update

[JGalego]

Features

• Added support for temporary credentials
• Added support for AWS credentials via environment variables (AWS_*)
  • https://github.com/geekan/MetaGPT/issues/1174#issuecomment-2096092836
• Updated supported models and corrected max tokens
  • New models
    • (AI21) Jamba-Instruct
    • (Amazon) Titan Text Premier
    • (Cohere) Command R & R+
    • (Mistral) Mistral Large 2
  • Legacy/EOL
    • (AI21) J2 Mid & Ultra for us-west-2
    • (Meta) Llama 2 (--> Llama 3/3.1)

Example

1. Add MetaGPT config

llm:
  api_type: 'bedrock'
  model: "amazon.titan-text-premier-v1:0"
  # 🔔 No need to add the access_key or secret_key!

2. Configure AWS Credentials

export AWS_ACCESS_KEY_ID=...
export AWS_SECRET_ACCESS_KEY=...
export AWS_SESSION_TOKEN=...
export AWS_DEFAULT_REGION=us-east-1

3. Call MetaGPT

metagpt "Create a 2048 game"