WorkerThreadsPool: Modernize std::result_of usage to C++17

Author: jlblancoc

libs/core/include/mrpt/core/WorkerThreadsPool.h

@@ -82,7 +82,7 @@ class WorkerThreadsPool
    * available. */
   template <class F, class... Args>
   [[nodiscard]] auto enqueue(F&& f, Args&&... args)
-      -> std::future<typename std::result_of<F(Args...)>::type>;
+      -> std::future<std::invoke_result_t<F(Args...)>>;
 
   /** Returns the number of enqueued tasks, currently waiting for a free
    * working thread to process them.  */
@@ -110,9 +110,9 @@ class WorkerThreadsPool
 
 template <class F, class... Args>
 auto WorkerThreadsPool::enqueue(F&& f, Args&&... args)
-    -> std::future<typename std::result_of<F(Args...)>::type>
+    -> std::future<std::invoke_result_t<F(Args...)>>
 {
-  using return_type = typename std::result_of<F(Args...)>::type;
+  using return_type = std::invoke_result_t<F(Args...)>;
 
   auto task = std::make_shared<std::packaged_task<return_type()>>(
       std::bind(std::forward<F>(f), std::forward<Args>(args)...));