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

h4ck3rm1k3/rspec-mocks,h4ck3rm1k3/rspec-mocks,maclover7/rspec-mocks,rspec/rspec-mocks,telekomatrix/rspec-mocks,telekomatrix/rspec-mocks,maclover7/rspec-mocks,rspec/rspec-mocks