message: docs: Update project structure page to remove docker/
diff: @@ -32,10 +32,6 @@ the code.
  better control over our `yarn.lock` file and hopefully avoid problems due to
  yarn versioning differences.
  -- [`docker/`](https://github.com/backstage/backstage/tree/master/docker) - Files
  - related to our root Dockerfile. We are planning to refactor this, so expect
  - this folder to be moved in the future.
  -
  - [`contrib/`](https://github.com/backstage/backstage/tree/master/contrib) -
  Collection of examples or resources provided by the community. We really
  appreciate contributions in here and encourage them being kept up to date.
  