Remove dead URL
Remove dead URL

The `rubysl/rubysl-yaml` repo and its issue tracker are gone, and there
doesn't seem to be an alternative URL.

yawboakye/rails,Erol/rails,Edouard-chin/rails,kmcphillips/rails,esparta/rails,kmcphillips/rails,georgeclaghorn/rails,kmcphillips/rails,rails/rails,esparta/rails,MSP-Greg/rails,esparta/rails,Erol/rails,Edouard-chin/rails,BlakeWilliams/rails,yahonda/rails,BlakeWilliams/rails,Edouard-chin/rails,Erol/rails,MSP-Greg/rails,MSP-Greg/rails,yawboakye/rails,esparta/rails,georgeclaghorn/rails,yahonda/rails,Edouard-chin/rails,rails/rails,yahonda/rails,kmcphillips/rails,yawboakye/rails,yawboakye/rails,yahonda/rails,rails/rails,georgeclaghorn/rails,Erol/rails,BlakeWilliams/rails,MSP-Greg/rails,georgeclaghorn/rails,rails/rails,BlakeWilliams/rails