CHANGELOG for v 20.6 and documentation change for sanic command (#1881)

* CHANGELOG for v 20.6 and documentation change for sanic command

* Update CHANGELOG.rst

20.6.0 and 20.6.1 are the same release. One change from `blueprints` had not made it in by accident, therefore the second subsequent release.

docs/sanic/deploying.rst

@@ -50,6 +50,12 @@ If you like using command line arguments, you can launch a Sanic webserver by
 executing the module. For example, if you initialized Sanic as `app` in a file
 named `server.py`, you could run the server like so:
 
+::
+
+    sanic server.app --host=0.0.0.0 --port=1337 --workers=4
+
+It can also be called directly as a module.
+
 ::
 
     python -m sanic server.app --host=0.0.0.0 --port=1337 --workers=4