Bump test-unit from 3.5.8 to 3.5.9

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.5.8 to 3.5.9.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.5.8...3.5.9)

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

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -446,7 +446,7 @@ GEM
     stripe (1.58.0)
       rest-client (>= 1.4, < 4.0)
     table_print (1.5.7)
-    test-unit (3.5.8)
+    test-unit (3.5.9)
       power_assert
     thor (1.2.2)
     tilt (2.0.10)