Merge pull request #534 from ruby/dependabot/bundler/test-unit-3.6.9

Bump test-unit from 3.6.8 to 3.6.9

Author: hsbt

Gemfile.lock

@@ -294,7 +294,7 @@ GEM
     sqlite3 (2.7.0-x86_64-linux-gnu)
     sqlite3 (2.7.0-x86_64-linux-musl)
     stringio (3.1.7)
-    test-unit (3.6.8)
+    test-unit (3.6.9)
       power_assert
     thor (1.3.2)
     timeout (0.4.3)