Bump test-unit from 3.6.8 to 3.6.9 (#3096)

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.6.8 to 3.6.9.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.6.8...3.6.9)

---
updated-dependencies:
- dependency-name: test-unit
  dependency-version: 3.6.9
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile

@@ -13,6 +13,6 @@ gem 'rubocop', '1.75.4'
 gem 'rubocop-minitest', '0.38.1'
 gem 'rubocop-rake', '0.7.1'
 gem 'simplecov', '0.22.0'
-gem 'test-unit', '3.6.8'
+gem 'test-unit', '3.6.9'
 gem 'timecop', '0.9.10'
 gem 'yard', '0.9.37'

Gemfile.lock

@@ -60,7 +60,7 @@ GEM
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.13.1)
     simplecov_json_formatter (0.1.4)
-    test-unit (3.6.8)
+    test-unit (3.6.9)
       power_assert
     timecop (0.9.10)
     unicode-display_width (3.1.4)
@@ -82,7 +82,7 @@ DEPENDENCIES
   rubocop-minitest (= 0.38.1)
   rubocop-rake (= 0.7.1)
   simplecov (= 0.22.0)
-  test-unit (= 3.6.8)
+  test-unit (= 3.6.9)
   timecop (= 0.9.10)
   yard (= 0.9.37)