Update external project to use gha vcpkg cache

.github/workflows/external.yml

@@ -3,7 +3,7 @@ name: windows-external-project
 on: [push, workflow_dispatch]
 
 env:
-  VCPKG_BINARY_SOURCES : 'clear;nuget,GitHub,readwrite'
+  VCPKG_BINARY_SOURCES : "clear;x-gha,readwrite"
   # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
   BUILD_TYPE: Release
   VCPKG_VERSION: 'master'
@@ -27,29 +27,21 @@ jobs:
       with:
         submodules: recursive
 
+    - name: Export GitHub Actions cache environment variables
+      uses: actions/github-script@v7
+      with:
+        script: |
+          core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
+          core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');
+
     - name: Cloning vcpkg main branch (windows)
       shell: 'bash'
       run: |
         cmake -E make_directory ${{ matrix.VCPKG_WORKSPACE }}
         cd ${{ matrix.VCPKG_WORKSPACE }}
         git clone https://github.com/microsoft/vcpkg
         ./vcpkg/bootstrap-vcpkg.bat -disableMetrics
-        ${{ matrix.VCPKG_WORKSPACE }}/vcpkg/vcpkg version
-
-    - name: 'Setup NuGet Credentials'
-      working-directory: ${{ matrix.VCPKG_WORKSPACE }}
-      shell: 'bash'
-      run: |
-        ${{ matrix.mono }} `./vcpkg/vcpkg fetch nuget | tail -n 1` \
-        sources add \
-        -source "https://nuget.pkg.github.com/${{ github.actor }}/index.json" \
-        -storepasswordincleartext \
-        -name "GitHub" \
-        -username "${{ github.actor }}" \
-        -password "${{ secrets.GITHUB_TOKEN }}" 
-        ${{ matrix.mono }} `./vcpkg/vcpkg fetch nuget | tail -n 1` \
-          setapikey "${{ secrets.GITHUB_TOKEN }}" \
-          -source "https://nuget.pkg.github.com/${{ github.actor }}/index.json"
+        ${{ matrix.VCPKG_WORKSPACE }}/vcpkg/vcpkg version    
 
     - name: Create Build Environment
       run: |