message: Fix broken link to nstar readme
  nstar doesn't have a readme. Remove broken link.
diff: @@ -145,7 +145,7 @@ The Northstar workspace configuration configures a cargo
  [runner](.cargo/runner-x86_64-unknown-linux-gnu) that invokes the runtimes
  example main binary with super user rights.
  -Use the [nstar](./northstar-nstar/README.md) utility to inspect and modify the
  +Use the [northstar-nstar](./northstar-nstar) utility to inspect and modify the
  runtimes state e.g.
  ```sh
  