Added overflow handling in JsonVariant::as<T>() and JsonVariant::is<T>()

test/JsonArray/subscript.cpp

@@ -22,7 +22,8 @@ TEST_CASE("JsonArray::operator[]") {
   SECTION("long long") {
     array[0] = 9223372036854775807;
     REQUIRE(9223372036854775807 == array[0].as<int64_t>());
-    REQUIRE(true == array[0].is<int>());
+    REQUIRE(true == array[0].is<int64_t>());
+    REQUIRE(false == array[0].is<int32_t>());
     REQUIRE(false == array[0].is<bool>());
   }
 #endif