By Sergio Goncalves and Miguel Pereira LISBON (Reuters) – Tens of thousands of public school teachers and other staff marched in Lisbon on Saturday to demand higher wages and better working conditions, putting further pressure on the Portuguese government as it grapples with a cost of living crisis. Shouting slogans like “for the banks there are millions, for us there are only pennies,” about 80,000 protesters filled the Portuguese capital, police said. A year after Socialist Prime Minister Antonio Costa won a majority in parliament, he is facing a slump in popularity and street protests not j…