Bump test-unit from 3.6.2 to 3.6.3

Bumps [test-unit](https://github.com/test-unit/test-unit) from 3.6.2 to 3.6.3.
- [Release notes](https://github.com/test-unit/test-unit/releases)
- [Commits](test-unit/test-unit@3.6.2...3.6.3)

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

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

Gemfile.lock

@@ -75,7 +75,7 @@ GEM
       sawyer (~> 0.9)
     phantomjs (2.1.1.0)
     pit (0.0.7)
-    power_assert (2.0.3)
+    power_assert (2.0.4)
     public_suffix (5.0.5)
     racc (1.7.3)
     rack (3.0.11)
@@ -125,7 +125,7 @@ GEM
     sync (0.5.0)
     term-ansicolor (1.7.1)
       tins (~> 1.0)
-    test-unit (3.6.2)
+    test-unit (3.6.3)
       power_assert
     thor (1.3.2)
     timeout (0.4.1)