DES MOINES — With a food bank striving to keep up with surging demand during the pandemic as his backdrop, Douglas Emhoff, the husband of Vice President Kamala Harris, announced Monday that federal benefits for people on SNAP — food stamps — will increase through September.Monday’s event, held at the Food Bank of Iowa in Des Moines, was organized by the White House to highlight the $1.9 trillion federal COVID-19 pandemic relief package.Emhoff was joined by U.S.