ci: make Windows workflow PowerShell 5 compatible

.gitea/workflows/build-windows-release.yml

@@ -61,9 +61,12 @@ jobs:
           }
 
           $bash = "$msysRoot\usr\bin\bash.exe"
-          & $bash -lc "pacman --noconfirm -Syuu" || $true
           & $bash -lc "pacman --noconfirm -Syuu"
+          if ($LASTEXITCODE -ne 0) { Write-Host '第一次 pacman 系统更新返回非零，继续执行第二次更新。' }
+          & $bash -lc "pacman --noconfirm -Syuu"
+          if ($LASTEXITCODE -ne 0) { throw "pacman 系统更新失败，退出码：$LASTEXITCODE" }
           & $bash -lc "pacman --noconfirm -S --needed git zip unzip p7zip mingw-w64-ucrt-x86_64-toolchain mingw-w64-ucrt-x86_64-cmake mingw-w64-ucrt-x86_64-ninja mingw-w64-ucrt-x86_64-qt6-base mingw-w64-ucrt-x86_64-qt6-imageformats"
+          if ($LASTEXITCODE -ne 0) { throw "pacman 安装依赖失败，退出码：$LASTEXITCODE" }
 
       - name: Configure and build
         shell: powershell