[CI] Cygwin tests failing on setup stage

[abravalheri]

I noticed earlier today that the Cygwin tests on Github Actions started to fail with the following error message:

Invoke-WebRequest : Unable to connect to the remote server
At D:\a\_temp\8190815c-a74b-45ab-8b4e-dfd48f6aa708.ps1:10 char:1
+ Invoke-WebRequest https://cygwin.com/setup-$platform.exe -OutFile C:\ ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebExc 
   eption
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand

Probably there is something wrong with the URL being used (e.g. https://cygwin.com/setup-x86_64.exe).
Moved recently? Down? Timeout?