Update redis to 6.2.11

Merge branch 'security-update-redis-to-6.2.11-15.10' into '15-10-stable'

See merge request gitlab-org/security/omnibus-gitlab!314

Changelog: security

config/software/redis.rb

@@ -25,7 +25,7 @@ skip_transitive_dependency_licensing true
 dependency 'config_guess'
 dependency 'openssl' unless Build::Check.use_system_ssl?
-version = Gitlab::Version.new('redis', '6.2.8')
+version = Gitlab::Version.new('redis', '6.2.11')
 default_version version.print(false)
 source git: version.remote