Remove some probable Hacktoberfest spam

I can't really figure out why this line would be here at all, let alone this location.  And Hacktoberfest is over anyway.  Probably just spam?

README.md

@@ -510,9 +510,6 @@ full disclosure.
 See: [security_specification.md](https://github.com/cjdelisle/cjdns/blob/master/doc/security_specification.md) to see if a
 possible security issue is really a security issue.
 
-That time of year again... Time for some open source Projects!
-[![Hacktoberfest](https://img.shields.io/badge/Open%20Source-Hacktoberfest-orange.svg)](https://hacktoberfest.digitalocean.com/)
-
 [IRC Web]: http://chat.efnet.org/irc.cgi?chan=%23cjdns
 [Hyperboria]: https://hyperboria.net
 [/r/darknetplan]: https://www.reddit.com/r/darknetplan