Fix CMake build

Author: t-sommer

.github/workflows/build.yml

@@ -19,8 +19,9 @@ jobs:
     - run: cmake --build cpp_build --config Release
     - run: cpp_build\Release\ExternalLibraryTest.exe
     - run: |
-        $python_home = "${{ env.Python_ROOT_DIR }}" -replace "\\", "/"
-        cmake . -G "Visual Studio 17 2022" -Bpython_build -DEXTERNAL_LANGUAGE=Python -DPYTHON_HOME="$python_home"
+        $python_exe = where python
+        $python_exe = $python_exe -replace "\\", "/"
+        cmake . -G "Visual Studio 17 2022" -B python_build -D EXTERNAL_LANGUAGE=Python -D PYTHON_EXE="$python_exe"
     - run: cmake --build python_build --config Release
     - run: python -m pip install -e Python
     - run: python_build\Release\ExternalLibraryTest.exe