Remove unnecessary : ( Colon ) (#286)

In line 37 and 50 there are :: ( two colons ) before the code-block 
Where it should be : ( One Colon )  to properly lint the code.

This pull request fixes this issue.

Author: baseplate-admin

README.rst

@@ -34,7 +34,7 @@ This package is for Channels 2 projects only.
 Usage
 -----
 
-Set up the channel layer in your Django settings file like so::
+Set up the channel layer in your Django settings file like so:
 
 .. code-block:: python
 
@@ -47,7 +47,7 @@ Set up the channel layer in your Django settings file like so::
         },
     }
 
-Or, you can use the alternate implementation which uses Redis Pub/Sub::
+Or, you can use the alternate implementation which uses Redis Pub/Sub:
 
 .. code-block:: python