Add second KL position to joinus.md.
Add second KL position to joinus.md.

PocketScienceLab/PocketScienceLab.github.io,PocketScienceLab/PocketScienceLab.github.io,stevelinton/OpenDreamKit.github.io,JohnCremona/OpenDreamKit.github.io,defeo/odk-hyde,PocketScienceLab/PocketScienceLab.github.io,PocketScienceLab/PocketScienceLab.github.io,JohnCremona/OpenDreamKit.github.io,defeo/odk-hyde,JohnCremona/OpenDreamKit.github.io,defeo/odk-hyde,stevelinton/OpenDreamKit.github.io,stevelinton/OpenDreamKit.github.io