message: docs(alerts & reports): clarify nature of "-dev" labeled container images
diff: @@ -43,6 +43,8 @@ All you need to do is add the required config variables described in this guide
  If you are running a non-dev docker image, e.g., a stable release like `apache/superset:2.0.1`, that image does not include a headless browser. Only the `superset_worker` container needs this headless browser to browse to the target chart or dashboard.
  You can either install and configure the headless browser - see "Custom Dockerfile" section below - or when deploying via `docker-compose`, modify your `docker-compose.yml` file to use a dev image for the worker container and a stable release image for the `superset_app` container.
  +*Note*: In this context, a "dev image" is the same application software as its corresponding non-dev image, just bundled with additional tools. So an image like `2.0.1-dev` is identical to `2.0.1` when it comes to stability, functionality, and running in production. The actual "in-development" versions of Superset - cutting-edge and unstable - are not tagged with version numbers on Docker Hub and will display version `0.0.0-dev` within the Superset UI.
  +
  #### Slack integration
  To send alerts and reports to Slack channels, you need to create a new Slack Application on your workspace.
  