Bump redis_exporter to version 1.51.0

- Update gitlab-org/build/omnibus-mirror/redis_exporter
  from 1.46.0 to 1.51.0

Changelog: changed

Author: [┐∵]┘GitLab Dependency Bot

config/software/redis-exporter.rb

@@ -20,7 +20,7 @@
 require 'time'
 
 name 'redis-exporter'
-version = Gitlab::Version.new('redis-exporter', '1.46.0')
+version = Gitlab::Version.new('redis-exporter', '1.51.0')
 default_version version.print
 
 license 'MIT'