[Feature]: Support for .prompt.yml files

[FidelusAleksander]

Would it make sense for this action to support GitHub Models .prompt.yml files?

I'm imagining the interface could be like:

steps:
  - name: Run AI Inference
    id: inference
    uses: actions/ai-inference@v1
    with:
      prompt-file: './.github/prompts/sample.prompt.yml'
      input: |
         var1: hello
         var2: ${{ steps.<some-step>.outputs.<output> }}
         var3: |
           Lorem Ipsum
           Hello World

Or maybe you can think of something better, non-breaking that would support the prompt files