Bump redis from 4.2.2 to 4.2.5 (#15202)

Bumps [redis](https://github.com/redis/redis-rb) from 4.2.2 to 4.2.5.
- [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/v4.2.2...v4.2.5)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -478,7 +478,7 @@ GEM
       link_header (~> 0.0, >= 0.0.8)
     rdf-normalize (0.4.0)
       rdf (~> 3.1)
-    redis (4.2.2)
+    redis (4.2.5)
     redis-actionpack (5.2.0)
       actionpack (>= 5, < 7)
       redis-rack (>= 2.1.0, < 3)