Bump test-unit from 3.6.2 to 3.6.4

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.6.2 to 3.6.4.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.6.2...3.6.4)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Gemfile

@@ -13,6 +13,6 @@ gem 'rubocop', '1.68.0'
 gem 'rubocop-minitest', '0.36.0'
 gem 'rubocop-rake', '0.6.0'
 gem 'simplecov', '0.22.0'
-gem 'test-unit', '3.6.2'
+gem 'test-unit', '3.6.4'
 gem 'timecop', '0.9.10'
 gem 'yard', '0.9.37'

Gemfile.lock

@@ -22,7 +22,7 @@ GEM
     parser (3.3.5.1)
       ast (~> 2.4.1)
       racc
-    power_assert (2.0.3)
+    power_assert (2.0.4)
     pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -54,7 +54,7 @@ GEM
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
-    test-unit (3.6.2)
+    test-unit (3.6.4)
       power_assert
     timecop (0.9.10)
     unicode-display_width (2.6.0)
@@ -74,7 +74,7 @@ DEPENDENCIES
   rubocop-minitest (= 0.36.0)
   rubocop-rake (= 0.6.0)
   simplecov (= 0.22.0)
-  test-unit (= 3.6.2)
+  test-unit (= 3.6.4)
   timecop (= 0.9.10)
   yard (= 0.9.37)