Add parallel for building

Author: Michael Grier

.github/workflows/cmake-multi-platform.yml

@@ -84,7 +84,7 @@ jobs:
 
     - name: Build
       # Build your program with the given configuration. Note that --config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
-      run: cmake --build ${{ steps.strings.outputs.build-output-dir }} --config ${{ matrix.build_type }}
+      run: cmake --build ${{ steps.strings.outputs.build-output-dir }} --config ${{ matrix.build_type }} --parallel
 
     - name: Test
       working-directory: ${{ steps.strings.outputs.build-output-dir }}