About 30 dogs in Superman capes showed up in the German city of Cologne for a special screening of the new animation film “DC League of Super-Pets” on Saturday. The animals are “petfluencers,” ie animals with far-reaching social media accounts. Their owners had applied for them to attend the special screening. Just like online influencers, the petfluencers share their lives with their fans on social media, promoting all kinds of things. “DC League of Super-Pets” follows the adventures of a dog called Krypto, as he tries to rescue the kidnapped Justice League of superheroes, including his owner…