- This change addresses an issue where the return type of handlers was not being correctly enforced by the TypeScript compiler. As far as I could tell, the issue is caused by the `infer` keyword not working with generic types.
- Added `TResult` as a type parameter to `MiddlewareHandler` to explicitly specify the handler's return type.
- Modified the `middy` function signature to pass `TResult` to `MiddlewareHandler`.
- By explicitly specifying `TResult`, we ensure that the compiler can correctly enforce the handler's return type.

closes #1228

🏷️ ensures that handler return is properly typed