Add Windows Server 2025 to the Windows version support policy

What does this MR do?

Add Windows Server 2025 support policy to the GitLab Runner support policy document

This MR needs to be merged in conjunction with !5170 (merged)

Why was this MR needed?

There is an active MR that will add support for Windows Server 2025 to Runner.

What are the relevant issue numbers?

#38316 (closed), #38246 (closed)

Merge request reports

Loading