action.yml

name: Get file from repository
description: Downloads a file from the repository using the github api.
inputs:
  path:  
    description: What file to get.
    required: true
  name:  
    description: Name of file after downloading to temp directory.
    required: true
  token:
    description: The token to use to query the Github API. Provided by the Actions context usually. 
    required: true
outputs:  
  path:
    description: The file locally after downloading.
    value: ${{ steps.get_file.outputs.path }}

runs:
  using: composite
  steps:
    - name: Get File
      shell: powershell
      id: get_file
      run: |
        $Url = "${{ github.api_url }}/repos/${{ github.repository }}/contents/${{ inputs.path }}?ref=${{ github.ref_name }}"
        $Headers = @{
            'authorization' = 'Bearer ${{ inputs.token }}'
        }
        $Response = Invoke-RestMethod $Url -Headers $Headers

        # Decode from Base64, Parse Yaml
        $Text = $Response.content | %{ [Text.Encoding]::UTF8.GetString([Convert]::FromBase64String($_)) } 
        $Path = "${{ runner.temp }}/${{ inputs.name }}"
        $Text | Out-File -FilePath $Path -Encoding UTF8
        echo "::set-output name=path::$Path"