Update dependency oj to v3.16.0 (mastodon#26520)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Gemfile.lock

@@ -482,7 +482,7 @@ GEM
     nokogiri (1.15.4)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    oj (3.15.0)
+    oj (3.16.0)
     omniauth (2.1.1)
       hashie (>= 3.4.6)
       rack (>= 2.2.3)