Update action.yml

Author: mcbarton

.github/actions/Build_and_Test_cppyy/action.yml

@@ -153,7 +153,7 @@ runs:
         # Build and Install cppyy-backend
         $env:INCLUDE=$env:CPLUS_INCLUDE_PATH
         cmake -DCppInterOp_DIR=$env:CPPINTEROP_DIR ..
-        cmake --build . --parallel ${{ env.ncpus }} -- -verbosity:diagnostic
+        cmake --build . --parallel ${{ env.ncpus }} -- /verbosity:diagnostic
         cp libcppyy-backend.lib $env:CPPINTEROP_DIR\lib\
         cd ..