Update CONTRIBUTING.md
Update CONTRIBUTING.md

Ajustes ortográficos.
wenderjean/RubyCastsBrasil,mfbmina/RubyCastsBrasil,laurow/RubyCastsBrasil,RubyCastsBrasil/RubyCastsBrasil,wenderjean/RubyCastsBrasil,castsbrasil/castsbrasil,mauriciomedeiros/RubyCastsBrasil,mauriciomedeiros/RubyCastsBrasil,castsbrasil/castsbrasil,castsbrasil/castsbrasil,jeanmatheussouto/RubyCastsBrasil,jeanmatheussouto/RubyCastsBrasil,mfbmina/RubyCastsBrasil,laurow/RubyCastsBrasil,wenderjean/RubyCastsBrasil,mauriciomedeiros/RubyCastsBrasil,RubyCastsBrasil/RubyCastsBrasil,mfbmina/RubyCastsBrasil,RubyCastsBrasil/RubyCastsBrasil,laurow/RubyCastsBrasil