* GSNSignatureBoucer does not accept zero address * Linting code. * Update contracts/GSN/bouncers/GSNBouncerSignature.sol Makes sense! Co-Authored-By: Nicolás Venturo <nicolas.venturo@gmail.com> * Update test/GSN/GSNBouncerSignature.test.js ok! Co-Authored-By: Nicolás Venturo <nicolas.venturo@gmail.com> * Add zero address constant from OZ test Helpers * revert prettier formatting