feat: support add ignore file

[bingryan]

filter ignore file list, eg:

steps:
  - uses: anc95/ChatGPT-CodeReview@main
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
      # add ignore
      IGNORE/ignore: |
        yarn.lock
        README.md

filter some files, such as README.md, yarn.lock/pnpm-lock.yaml,.gitignore, etc

for my resp: https://github.com/bingryan/WeChatAI/pull/52/files/64c88fa7c4c2b784ccfcb456c9f850649a3436d4
I hope the bot do not review .gitignore and pnpm-lock.yaml.

[anc95]

Thank you