Fix invoke task to only parse date if there is one
Fix invoke task to only parse date if there is one

alexgarciac/scrapi,mehanig/scrapi,CenterForOpenScience/scrapi,CenterForOpenScience/scrapi,felliott/scrapi,erinspace/scrapi,mehanig/scrapi,felliott/scrapi,fabianvf/scrapi,ostwald/scrapi,jeffreyliu3230/scrapi,icereval/scrapi,erinspace/scrapi,fabianvf/scrapi