Update CONTRIBUTING.md
Update CONTRIBUTING.md

Fixed clone / upstream url
citiususc/hipster,kigsmtua/hipster,artfullyContrived/hipster,nkhuyu/hipster,citiususc/hipster,Navaneethsen/hipster,artfullyContrived/hipster,nkhuyu/hipster,pablormier/hipster,gabizekany/hipster,kigsmtua/hipster,nkhuyu/hipster,kigsmtua/hipster,pablormier/hipster,gabizekany/hipster,Navaneethsen/hipster,citiususc/hipster,artfullyContrived/hipster,pablormier/hipster,Navaneethsen/hipster,gabizekany/hipster