modified: README.md

Removes the warning for step 4 from the installation guide. The warning said not to run migrations
as the plugin did not have its own models. Since v0.9.6 it does so this was forgotten to be removed.

README.md

@@ -109,7 +109,7 @@ This guide assumes:
     This allows the plugin to map requests to the right dns view using the tsig
     signature from each request.
 
-4. Run migrations (This step is not yet required. Just adding for completeness)
+4. Run migrations
     ```
     python3 netbox/manage.py migrate
     ```