[Inkscape-docs] contest deadline

Hi Friends, Nov 13th is the date being circulated as the deadline for the About Screen Contest. For some reason, I thought it was the 8th. I'm thinking it would be good to have the deadline date mentioned on the instructions page. And I would do it myself, except I'm not 100% positive that it's the 13th. If we can confirm the date, I'll add it to the page :-) Thanks, brynn