Merge pull request #65 from alphagov/dependabot/bundler/redis-5.4.0

Bump redis from 5.3.0 to 5.4.0

Author: andysellick

Gemfile.lock

@@ -489,7 +489,7 @@ GEM
     rake (13.2.1)
     rdoc (6.12.0)
       psych (>= 4.0.0)
-    redis (5.3.0)
+    redis (5.4.0)
       redis-client (>= 0.22.0)
     redis-client (0.23.2)
       connection_pool