CI: github: disable windows.yml by default on unofficials repo

Disable the windows job for repository in repositories that are not in
the "haproxy" organization. This is mostly used for portability during
development and only making noise during the maintenance cycle.

Must be backported in every branches.

.github/workflows/windows.yml

@@ -18,6 +18,7 @@ jobs:
   msys2:
     name: ${{ matrix.name }}
     runs-on: ${{ matrix.os }}
+    if: ${{ github.repository_owner == 'haproxy' || github.event_name == 'workflow_dispatch' }}
     defaults:
       run:
         shell: msys2 {0}