Update extensions.json

fix: name

Author: Maksimall89

src/data/doc-extensions/extensions.json

@@ -1103,7 +1103,7 @@
       "url": "https://github.com/Maksimall89/xk6-output-clickhouse",
       "logo": "",
       "author": {
-        "name": "Maksimall89,
+        "name": "Maksimall89",
         "url": "https://github.com/Maksimall89"
       },
       "stars": "2",