Bump redis from 4.0.1 to 4.0.2 (#8850)

Bumps [redis](https://github.com/redis/redis-rb) from 4.0.1 to 4.0.2.
- [Release notes](https://github.com/redis/redis-rb/releases)
- [Changelog](https://github.com/redis/redis-rb/blob/master/CHANGELOG.md)
- [Commits](https://github.com/redis/redis-rb/compare/v4.0.1...v4.0.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Gemfile.lock

@@ -472,7 +472,7 @@ GEM
       link_header (~> 0.0, >= 0.0.8)
     rdf-normalize (0.3.3)
       rdf (>= 2.2, < 4.0)
-    redis (4.0.1)
+    redis (4.0.2)
     redis-actionpack (5.0.2)
       actionpack (>= 4.0, < 6)
       redis-rack (>= 1, < 3)