Bump redis from 4.5.1 to 4.8.1

Bumps [redis](https://github.com/redis/redis-rb) from 4.5.1 to 4.8.1.
- [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/v4.5.1...v4.8.1)

---
updated-dependencies:
- dependency-name: redis
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile

@@ -73,7 +73,7 @@ gem 'rack-cors', '~> 1.1', require: 'rack/cors'
 gem 'rails-i18n', '~> 6.0'
 gem 'rails-settings-cached', '~> 0.6'
 gem 'redcarpet', '~> 3.5'
-gem 'redis', '~> 4.5', require: ['redis', 'redis/connection/hiredis']
+gem 'redis', '~> 4.8', require: ['redis', 'redis/connection/hiredis']
 gem 'mario-redis-lock', '~> 1.2', require: 'redis_lock'
 gem 'rqrcode', '~> 2.1'
 gem 'ruby-progressbar', '~> 1.11'

Gemfile.lock

@@ -541,7 +541,7 @@ GEM
     rdf-normalize (0.5.0)
       rdf (~> 3.2)
     redcarpet (3.5.1)
-    redis (4.5.1)
+    redis (4.8.1)
     redis-namespace (1.9.0)
       redis (>= 4)
     regexp_parser (2.5.0)
@@ -824,7 +824,7 @@ DEPENDENCIES
   random_name_generator
   rdf-normalize (~> 0.5)
   redcarpet (~> 3.5)
-  redis (~> 4.5)
+  redis (~> 4.8)
   redis-namespace (~> 1.9)
   rexml (~> 3.2)
   rqrcode (~> 2.1)