Merge pull request #336 from ruby-syntax-tree/dependabot/bundler/minitest-5.18.0

Bump minitest from 5.17.0 to 5.18.0

Author: github-actions[bot]

Gemfile.lock

@@ -10,7 +10,7 @@ GEM
     ast (2.4.2)
     docile (1.4.0)
     json (2.6.3)
-    minitest (5.17.0)
+    minitest (5.18.0)
     parallel (1.22.1)
     parser (3.2.1.0)
       ast (~> 2.4.1)