updated bio (#4367)

Co-authored-by: Barry Pollard <barrypollard@google.com>

Author: nrllh

src/config/contributors.json

@@ -3829,7 +3829,7 @@
         "reviewers"
       ]
     },
-    "twitter": "nrllah",
+    "linkedin": "nurullahdemir",
     "website": "https://ndemir.com"
   },
   "oluoluoxenfree": {