Remove CppCon from community-sponsor

Co-Authored-By: Kate Gregory <[email protected]>

Author: claremacrae

community-sponsors.md

@@ -9,7 +9,6 @@ Many conferences, organizations, and websites help to promote us in a variety of
 
 * [ACCU](https://accu.org)
 * [C++ on Sea](https://cpponsea.uk)
-* [CppCon](https://cppcon.org)
 * [CPPP](https://cppp.fr)
 * [Meeting C++](https://meetingcpp.com)