feat: add self define repo

[bxb100]

support creates an issue to other repo

[bxb100]

fixed, cc @JasonEtco

At first, I consider manual override GITHUB_TOKEN by a specific PAT like this:

    - uses: bxb100/create-an-issue@v2
      env:
        GITHUB_TOKEN: ${{ secrets.GH_PAT }}
      with:
        repository: bxb100/bxb100.github.io
        filename: README.md
        update_existing: true
        search_existing: all

and it is equal to github.token^1.

following your opinion, I give the concise parameter token in the action.yml.