Fix nvcc compile error (#2477)

Co-authored-by: Niels Kristian Kjærgård Madsen <nkm@kvantify.dk>

src/catch2/benchmark/catch_constructor.hpp

@@ -59,7 +59,7 @@ namespace Catch {
                 }
 
                 T const& stored_object() const {
-                    return *static_cast<T*>(static_cast<void*>(data));
+                    return *static_cast<T const*>(static_cast<void const*>(data));
                 }