Bump test-unit from 3.7.6 to 3.7.7

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.7.6 to 3.7.7.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.7.6...3.7.7)

---
updated-dependencies:
- dependency-name: test-unit
  dependency-version: 3.7.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -10,7 +10,7 @@ GEM
     rouge (4.7.0)
     syntax_tree (6.3.0)
       prettier_print (>= 1.2.0)
-    test-unit (3.7.6)
+    test-unit (3.7.7)
       power_assert
 
 PLATFORMS