Scope guards noexecpt value updated according R8 (#121).

include/detail/scope_guard_base.h

             std::enable_if_t<(!std::is_lvalue_reference_v<EFP>)
                                 && std::is_nothrow_constructible_v<EF, EFP>, int> = 0
             >
-        explicit scope_guard_base(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>)
+        explicit scope_guard_base(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>
+                                                                || std::is_nothrow_constructible_v<EF, EFP&>)
                                                     : m_exitfunction(std::move(exitFunction)),
                                                     m_execute_on_destruction(true)
         {

include/scope_exit.h

             std::enable_if_t<std::is_constructible_v<EF, EFP>, int> = 0,
             std::enable_if_t<!std::is_same_v<detail::remove_cvref_t<EFP>, scope_exit<EF>>, int> = 0
             >
-        explicit scope_exit(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>)
+        explicit scope_exit(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>
+                                                        || std::is_nothrow_constructible_v<EF, EFP&>)
                                                 : Base(std::forward<EFP>(exitFunction))
         {
         }

include/scope_fail.h

             std::enable_if_t<std::is_constructible_v<EF, EFP>, int> = 0,
             std::enable_if_t<!std::is_same_v<detail::remove_cvref_t<EFP>, scope_fail<EF>>, int> = 0
             >
-        explicit scope_fail(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>)
+        explicit scope_fail(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>
+                                                            || std::is_nothrow_constructible_v<EF, EFP&>)
                                                 : Base(std::forward<EFP>(exitFunction))
         {
         }

include/scope_success.h

             std::enable_if_t<std::is_constructible_v<EF, EFP>, int> = 0,
             std::enable_if_t<!std::is_same_v<detail::remove_cvref_t<EFP>, scope_success<EF>>, int> = 0
             >
-        explicit scope_success(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>)
+        explicit scope_success(EFP&& exitFunction) noexcept(std::is_nothrow_constructible_v<EF, EFP>
+                                                            || std::is_nothrow_constructible_v<EF, EFP&>)
                                                 : Base(std::forward<EFP>(exitFunction))
         {
         }