Updated nlohmann::json to latest version 3.9.1 to resolve compiler issues with GCC 9 and 10 (#438)
Updated nlohmann::json to latest version 3.9.1 to resolve compiler issues with GCC 9 and 10 (#438)

* Updated nlohmann::json to latest version 3.9.1 to resolve compiler issues with GCC 9 and 10
lsils/mockturtle,lsils/mockturtle,lsils/mockturtle,lsils/mockturtle