Update README

README.md

 | domain_fronting_traffic     | counter | `direction`                      | Count of bytes, transmitted to/from fronting domain.                                       |
 | domain_fronting             | counter | –                                | Count of domain fronting events.                                                           |
 | concurrency_limited         | counter | –                                | Count of events, when client connection was rejected due to concurrency limit.             |
-| ip_blocklisted              | counter | –                                | Count of events when client connection was rejected because IP was found in the blacklist. |
+| ip_blocklisted              | counter | `ip_list`                        | Count of events when client connection was rejected because IP was found in the blocklist. |
 | replay_attacks              | counter | –                                | Count of detected replay attacks.                                                          |
 
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