Update Rake task logging expectation

a8b0f53 bumped `govuk_app_config` from 9.11.2 to 9.12.0, which set the
`time_zone` to London in all GOV.UK apps. This appears to change how the
timezone is reported when calling `updated_at` on a record: what was
`UTC` is now `+0000`. This change resulted in a couple of failing tests,
but only related to console logging within a Rake task, so we should be
fine just to update our expectations here

spec/lib/tasks/data_hygiene/content_item_deduplicator_spec.rb

@@ -14,10 +14,10 @@
       create(:content_item, content_id: content_item.content_id, locale: "en")
 
       expect(Rails.logger).to receive(:info).with("These duplicates were destroyed...")
-      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},cy,2020-02-27 00:00:00 UTC,#{content_item.base_path}")
+      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},cy,2020-02-27 00:00:00 +0000,#{content_item.base_path}")
       expect(Rails.logger).to receive(:info).twice.with("-----------------------------------------------------------------")
       expect(Rails.logger).to receive(:info).with("These records were preserved...")
-      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},cy,2020-02-27 00:00:00 UTC,#{content_item2.base_path}")
+      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},cy,2020-02-27 00:00:00 +0000,#{content_item2.base_path}")
       expect(Rails.logger).to receive(:info).with("2 duplicates found.")
       expect(Rails.logger).to receive(:info).with("1 records were removed.")
       expect(Rails.logger).to receive(:info).with("1 records were preserved.")
@@ -33,10 +33,10 @@
       create(:content_item, content_id: content_item.content_id, locale: "fr")
 
       expect(Rails.logger).to receive(:info).with("These duplicates would be destroyed...")
-      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},en,2020-02-27 00:00:00 UTC,#{content_item.base_path}")
+      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},en,2020-02-27 00:00:00 +0000,#{content_item.base_path}")
       expect(Rails.logger).to receive(:info).twice.with("-----------------------------------------------------------------")
       expect(Rails.logger).to receive(:info).with("These records would be preserved...")
-      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},en,2020-02-27 00:00:00 UTC,#{content_item2.base_path}")
+      expect(Rails.logger).to receive(:info).with("#{content_item.content_id},en,2020-02-27 00:00:00 +0000,#{content_item2.base_path}")
       expect(Rails.logger).to receive(:info).with("2 duplicates found.")
       expect(Rails.logger).to receive(:info).with("1 records would be removed.")
       expect(Rails.logger).to receive(:info).with("1 records would be preserved.")