add telemetry info

Author: guimachiavelli

learn/resources/telemetry.mdx

@@ -273,3 +273,5 @@ This list is liable to change with every new version of Meilisearch. It's not be
 | `export.avg_index_patterns`          | Average number of index patterns set per export                  | `3.2`
 | `export.avg_patterns_with_filter`    | Average number of index patterns with filters per export         | `1.7`
 | `export.avg_payload_size`            | Average payload size per export                                  | `512`
+| `webhooks_created`                   | Number of webhooks created in an instance                                  | `2`
+| `webhooks.updated`                   | Number of times all webhooks in an instance have been updated                                  | `5`