Merge branch 'fix-danger-gemfile-warning' into 'master'

Fix duplicated suggestion in Danger gem warning

See merge request gitlab-org/gitlab-ce!31088

danger/gemfile/Dangerfile

@@ -3,8 +3,7 @@ GEMFILE_LOCK_NOT_UPDATED_MESSAGE = <<~MSG.freeze
 
 Usually, when %<gemfile>s is updated, you should run
 ```
-bundle install && \
-  bundle install
+bundle install
 ```
 
 or