Update `Gemfile.lock`.

Library/Homebrew/test/Gemfile.lock

@@ -36,7 +36,7 @@ GEM
     rspec-support (3.7.1)
     rspec-wait (0.0.9)
       rspec (>= 3, < 4)
-    rubocop (0.54.0)
+    rubocop (0.55.0)
       parallel (~> 1.10)
       parser (>= 2.5)
       powerpack (~> 0.1)
@@ -62,7 +62,7 @@ DEPENDENCIES
   rspec-its
   rspec-retry
   rspec-wait
-  rubocop (= 0.54.0)
+  rubocop (= 0.55.0)
   simplecov
 
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