Non-const deleter accessor implemented.

include/unique_resource.h

             return m_deleter;
         }
 
+        Deleter& get_deleter() noexcept
+        {
+            return m_deleter;
+        }
 
         unique_resource_t& operator=(unique_resource_t&& other) noexcept
         {

test/UniqueResourceTest.cpp

     guard.get_deleter()(6);
     REQUIRE(value == 6);
 }
+