Merge pull request #2122 from freeCodeCamp/renovate/minitest-5.x-lockfile

chore(deps): update dependency minitest to v5.21.1

Author: renovate[bot]

Gemfile.lock

@@ -53,7 +53,7 @@ GEM
     in_threads (1.6.0)
     method_source (1.0.0)
     mini_portile2 (2.8.4)
-    minitest (5.20.0)
+    minitest (5.21.1)
     multi_json (1.15.0)
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)