Gets file content from repository and deploys that as a Gist

Invoke-GistDeployment.ps1

<#
.Synopsis
   Gets file content from repository and deploys that as a Gist.
.DESCRIPTION
   Used in a GitHub action that automatically deploys your private repository file content as a secret Gist for example.
   You must provide GitHub Personal access Token, target Gist ID and Gist filename
.PARAMETER Token
    GitHub Personal Access Token with Gist scope
.PARAMETER GistID
    GitHub Gist ID
.PARAMETER GistFileName
    GitHub Gist filename
.PARAMETER ContentFileName
    Local repository filename where you get the content for the Gist
.EXAMPLE
   ./Invoke-GistDeployment.ps1 -Token ${env:TOKEN} -GistID ${env:GIST_ID} -GistFileName 'secret.md'
#>

param(
    [Parameter(Mandatory)]
    [String]$Token,

    [Parameter(Mandatory)]
    [String]$GistID,

    [Parameter(Mandatory)]
    [String]$GistFileName,

    [String]$ContentFileName = 'README.md'
)

[string]$fileContent = Get-Content $ContentFileName -Raw -Encoding utf8

# JSON payload for the GitHub API
$body = @{
  "files" = @{
    $gistFileName = @{
      "content" = $fileContent
    }
  }
} | ConvertTo-Json

$APIWebRequestParams = @{
  Uri = "https://api.github.com/gists/$GistID"
  Method = 'Patch'
  Body = $body
  ContentType = 'application/json; charset=utf-8'
  Headers = @{Authorization = "Token $Token"}
}

Invoke-RestMethod @APIWebRequestParams