Fixed parse error

Author: drowaudio

.github/workflows/build.yml

@@ -31,4 +31,4 @@ jobs:
         env:
           GENERATOR: ${{ matrix.generator }}
         run: |
-          ctest --build-and-test . ./build_$OSTYPE --build-generator "${{ env.GENERATOR }}" --test-command ctest -C ${{ env.$BUILD_CONFIG }} --verbose
+          ctest --build-and-test . ./build_$OSTYPE --build-generator "${{ matrix.generator }}" --test-command ctest -C ${{ env.BUILD_CONFIG }} --verbose