Merge pull request #538 from ruby/dependabot/bundler/test-unit-3.7.0

Bump test-unit from 3.6.9 to 3.7.0

Author: hsbt

Gemfile.lock

@@ -298,7 +298,7 @@ GEM
     sqlite3 (2.7.2-x86_64-linux-gnu)
     sqlite3 (2.7.2-x86_64-linux-musl)
     stringio (3.1.7)
-    test-unit (3.6.9)
+    test-unit (3.7.0)
       power_assert
     thor (1.4.0)
     timeout (0.4.3)