small README.md fix

Author: Bob Bui

README.md

@@ -10,7 +10,7 @@ If you're using Cloud Foundry, it might worth to check out the library [SAP/cf-p
    2.3 [Get current correlation-id](#23-get-current-correlation-id)  
    2.4 [Log extra properties](#24-log-extra-properties)  
    2.5 [Root logger](#25-root-logger)  
-   2.6 [Custom log formatter](#26-custom-log-formatter)
+   2.6 [Custom log formatter](#26-custom-log-formatter)  
    2.7 [Exclude certain URl from request instrumentation](#27-exclude-certain-url-from-request-instrumentation)
 3. [Configuration](#3-configuration)  
 4. [Python References](#4-python-references)