Update docs on disabling built-in logging

The current documentation recommends overriding the logging level for the entire Microsoft namespace, but this also suppresses logging for other Microsoft products, such as Entity Framework Core. Suggest updating this to recommend overriding Microsoft.AspNetCore instead.

Author: davidcoghlan

README.md

@@ -109,10 +109,10 @@ Or [as JSON](https://github.com/serilog/serilog-formatting-compact):
 }
 ```
 
-To enable the middleware, first change the minimum level for `Microsoft` to `Warning` in your logger configuration or _appsettings.json_ file:
+To enable the middleware, first change the minimum level for `Microsoft.AspNetCore` to `Warning` in your logger configuration or _appsettings.json_ file:
 
 ```csharp
-            .MinimumLevel.Override("Microsoft", LogEventLevel.Warning)
+            .MinimumLevel.Override("Microsoft.AspNetCore", LogEventLevel.Warning)
 ```
 
 Then, in your application's _Startup.cs_, add the middleware with `UseSerilogRequestLogging()`: