GitHub Actions: Using the correct triplet.

* .github/workflows/cmake.yml
  (win deps): Export VCPKG_TARGET_TRIPLET environment variable from the
   step; this will use the dependencies installed on this configuration.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1920784 13f79535-47bb-0310-9956-ffa450edef68

.github/workflows/cmake.yml

@@ -76,6 +76,7 @@ jobs:
             apr apr-util expat zlib sqlite3
 
           "CMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake" >> $env:GITHUB_ENV
+          "VCPKG_TARGET_TRIPLET=${{ matrix.vcpkg_triplet }}" >> $env:GITHUB_ENV
 
       - name: Install dependecies (Linux, apt-get)
         if: runner.os == 'Linux'