fix link to the Code of Conduct from the Contributing guide
fix link to the Code of Conduct from the Contributing guide

arronmabrey/rspec-core,azbshiri/rspec-core,rspec/rspec-core,azbshiri/rspec-core,maclover7/rspec-core,h4ck3rm1k3/rspec-core,h4ck3rm1k3/rspec-core,xmik/rspec-core,yaoshipu/rspec-core,arronmabrey/rspec-core,xmik/rspec-core,rspec/rspec-core,arronmabrey/rspec-core,maclover7/rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core,h4ck3rm1k3/rspec-core,yaoshipu/rspec-core,azbshiri/rspec-core,yaoshipu/rspec-core,maclover7/rspec-core,rspec/rspec-core,xmik/rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core,Teino1978-Corp/Teino1978-Corp-rspec-core