GHA CI: simplify vcpkg commands

.github/workflows/ci_windows.yaml

@@ -44,26 +44,13 @@ jobs:
 
       - name: Install dependencies from vcpkg
         run: |
-          # tell vcpkg to only build Release variants of the dependencies
-          New-Item `
-            -Path "${{ github.workspace }}" `
-            -Name "triplets_overlay" `
-            -ItemType Directory
-          Copy-Item `
-            "${{ env.RUNVCPKG_VCPKG_ROOT }}/triplets/x64-windows-static.cmake" `
-            "${{ github.workspace }}/triplets_overlay/x64-windows-static-release.cmake"
-          Add-Content `
-            "${{ github.workspace }}/triplets_overlay/x64-windows-static-release.cmake" `
-            -Value "set(VCPKG_BUILD_TYPE release)"
           # clear buildtrees after each package installation to reduce disk space requirements
           $packages = `
             "openssl:x64-windows-static-release",
             "zlib:x64-windows-static-release"
           ${{ env.RUNVCPKG_VCPKG_ROOT }}/vcpkg.exe upgrade `
-            --overlay-triplets="${{ github.workspace }}/triplets_overlay" `
             --no-dry-run
           ${{ env.RUNVCPKG_VCPKG_ROOT }}/vcpkg.exe install `
-            --overlay-triplets="${{ github.workspace }}/triplets_overlay" `
             --clean-after-build `
             $packages