Bump test-unit from 3.2.3 to 3.5.5 (#20)

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.2.3 to 3.5.5.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.2.3...3.5.5)

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

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -143,7 +143,7 @@ GEM
     omniauth_cobot (0.2.0)
       omniauth-oauth2 (~> 1.8.0)
     pg (0.19.0)
-    power_assert (0.4.1)
+    power_assert (2.0.2)
     public_suffix (5.0.0)
     puma (5.6.4)
       nio4r (~> 2.0)
@@ -210,7 +210,7 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
-    test-unit (3.2.3)
+    test-unit (3.5.5)
       power_assert
     thor (1.1.0)
     thread_safe (0.3.6)