Bump test-unit from 3.3.1 to 3.3.2 (#524)

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.3.1 to 3.3.2.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.3.1...3.3.2)

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

Gemfile.lock

@@ -163,7 +163,7 @@ GEM
     sqlite3 (1.4.0)
     term-ansicolor (1.7.1)
       tins (~> 1.0)
-    test-unit (3.3.1)
+    test-unit (3.3.2)
       power_assert
     therubyracer (0.12.3)
       libv8 (~> 3.16.14.15)