Upon final passage the City secretary shall give notice of the enactment of every ordinance imposing a penalty, fine, or forfeiture for any violation of any of its provisions of every other ordinance as required by law by causing the ordinance or its descriptive caption and penalty to be published at least one time in the official newspaper of the city. An affidavit of such publication shall be received from the newspaper by the City secretary and shall be conclusive proof of the legal publication and promulgation of such ordinance in all courts of the state.