Change require auth to use require auth2

[lucca65]

we should update it to use require_auth2() to use a new permission (we need to decide its name). This will avoid a malicious attack to change the contract's code

[lucca65]

https://github.com/EOSIO/eosio.cdt/blob/a6b8d3fc289d46f4612588cdd7223a3d549238f6/libraries/eosiolib/contracts/eosio/action.hpp#L39