Removed pre-release and HACS custom repo information

Author: apop880

README.md

@@ -18,9 +18,7 @@ configuration is valid._
 
 This app is best installed using
 [HACS](https://github.com/custom-components/hacs), so that you can easily track
-and download updates. Currently, the repository must be added manually on the
-Settings page. Once the app moves out of pre-release status, I will submit it to
-the default list.
+and download updates.
 
 Alternatively, you can download the `check-config` directory from inside the `apps` directory here to your
 local `apps` directory, then add the configuration to enable the `checkconfig`