Install scripts report HTTP 403 when running on an out of support platform

On Windows-Arm:

```ps
PS C:\Users\Bryce> powershell -ExecutionPolicy ByPass -c "irm https://dbc.columnar.tech/install.ps1 | iex"
Downloading dbc latest (aarch64-pc-windows-msvc)
Exception calling "DownloadFile" with "2" argument(s): "The remote server returned an error: (403) Forbidden."
PS C:\Users\Bryce>
```