Bump redis-namespace from 1.7.0 to 1.8.0 (#14623)

Bumps [redis-namespace](https://github.com/resque/redis-namespace) from 1.7.0 to 1.8.0.
- [Release notes](https://github.com/resque/redis-namespace/releases)
- [Changelog](https://github.com/resque/redis-namespace/blob/master/CHANGELOG.md)
- [Commits](https://github.com/resque/redis-namespace/compare/v1.7.0...v1.8.0)

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

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

Gemfile

@@ -56,7 +56,7 @@ gem 'fast_blank', '~> 1.0'
 gem 'fastimage'
 gem 'goldfinger', '~> 2.1'
 gem 'hiredis', '~> 0.6'
-gem 'redis-namespace', '~> 1.7'
+gem 'redis-namespace', '~> 1.8'
 gem 'health_check', git: 'https://github.com/ianheggie/health_check', ref: '0b799ead604f900ed50685e9b2d469cd2befba5b'
 gem 'htmlentities', '~> 4.3'
 gem 'http', '~> 4.4'