message: [docs] update url in CONTRIBUTING.md
diff: @@ -144,7 +144,7 @@ referenced in the rst, e.g.
  aren't actually included in that directory. _Instead_, you'll want to add and commit
  images (and any other static assets) to the _superset/assets/images_ directory.
  -When the docs are being pushed to [airbnb.io](http://airbnb.io/superset/), images
  +When the docs are being pushed to [Apache Superset (incubating)](https://superset.incubator.apache.org/), images
  will be moved from there to the _\_static/img_ directory, just like they're referenced
  in the docs.
  @@ -161,12 +161,12 @@ instead.
  ## Setting up a Python development environment
  -Check the [OS dependencies](http://airbnb.io/superset/installation.html#os-dependencies) before follows these steps.
  +Check the [OS dependencies](https://superset.incubator.apache.org/installation.html#os-dependencies) before follows these steps.
  # fork the repo on GitHub and then clone it
  # alternatively you may want to clone the main repo but that won't work
  # so well if you are planning on sending PRs
  - # git clone git@github.com:airbnb/superset.git
  + # git clone git@github.com:apache/incubator-superset.git
  # [optional] setup a virtual env and activate it
  virtualenv env
  @@ -379,4 +379,4 @@ to take effect, they need to be compiled using this command:
  Here's an example as a Github PR with comments that describe what the
  different sections of the code do:
  -https://github.com/airbnb/superset/pull/3013
  +https://github.com/apache/incubator-superset/pull/3013
  