Merge pull request #2053 from nlohmann/gcc10warnings

Fix GCC compiler warnings

test/src/unit-allocator.cpp

@@ -272,8 +272,8 @@ TEST_CASE("bad my_allocator::construct")
               double,
               allocator_no_forward>;
 
-        bad_alloc_json json;
-        json["test"] = bad_alloc_json::array_t();
-        json["test"].push_back("should not leak");
+        bad_alloc_json j;
+        j["test"] = bad_alloc_json::array_t();
+        j["test"].push_back("should not leak");
     }
 }