message: readme: delete coverity
  Coverity scan appears to be no more sadly. Delete for now until we
  figure out whether it is coming back and if not what to replace it
  with.
diff: Envoy is hosted by the [Cloud Native Computing Foundation](https://cncf.io) (CNCF). If you are a company that wants to help shape the evolution of technologies that are container-packaged, dynamically-scheduled and microservices-oriented, consider joining the CNCF. For details about who's involved and how Envoy plays a role, read the CNCF [announcement](https://www.cncf.io/blog/2017/09/13/cncf-hosts-envoy/).
  [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1266/badge)](https://bestpractices.coreinfrastructure.org/projects/1266)
  -[![Coverity](https://scan.coverity.com/projects/10180/badge.svg)](https://scan.coverity.com/projects/envoy-proxy)
  ## Documentation
  