Public/Add-GitHubPath.ps1

function Add-GitHubPath {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory)]
        [ValidateNotNullOrEmpty()]
        [string] $Path
    )

    $filePath = Get-GitHubEnvironmentFilePath -VariableName 'GITHUB_PATH'
    $Path | Out-File -FilePath $filePath -Append -Encoding utf8
}