let ninja decide how many processes to launch

.github/workflows/compile-msvc.yml

@@ -58,7 +58,7 @@ jobs:
         python3 -m pip install numpy
         python3 -m pip install pyyaml
         cmake -C cmake\presets\windows.cmake -D CMAKE_CXX_COMPILER=cl -D CMAKE_CXX_COMPILER_LAUNCHER=ccache -D CMAKE_C_COMPILER=cl -D CMAKE_C_COMPILER_LAUNCHER=ccache -D CMAKE_Fortran_COMPILER="" -D DOWNLOAD_POTENTIALS=off -D PKG_PYTHON=on -D WITH_PNG=off -D WITH_JPEG=off -S cmake -B build -D BUILD_SHARED_LIBS=on -D ENABLE_TESTING=on -G Ninja
-        cmake --build build --parallel 2
+        cmake --build build
 
     - name: Run LAMMPS executable
       run: |