Update redis requirement from ~> 4.1 to >= 4.1, < 6.0

Updates the requirements on [redis](https://github.com/redis/redis-rb) to permit the latest version.
- [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/v4.7.1...v5.0.3)

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

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

Gemfile.lock

@@ -18,7 +18,7 @@ PATH
       puma (~> 5.0, >= 5.0.4)
       rack (~> 2.2)
       rake (~> 13.0)
-      redis (~> 4.1)
+      redis (>= 4.1, < 6.0)
       sinatra (~> 2.0)
       spicy-proton (~> 2.1)
       statsd-ruby (~> 1.4)
@@ -111,7 +111,10 @@ GEM
       rack (>= 1.3)
     rainbow (3.1.1)
     rake (13.0.6)
-    redis (4.7.1)
+    redis (5.0.3)
+      redis-client (>= 0.7.4)
+    redis-client (0.7.4)
+      connection_pool
     regexp_parser (2.5.0)
     rexml (3.2.5)
     rspec (3.11.0)

vmpooler.gemspec

@@ -32,7 +32,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'puma', '~> 5.0', '>= 5.0.4'
   s.add_dependency 'rack', '~> 2.2'
   s.add_dependency 'rake', '~> 13.0'
-  s.add_dependency 'redis', '~> 4.1'
+  s.add_dependency 'redis', '>= 4.1', '< 6.0'
   s.add_dependency 'sinatra', '~> 2.0'
   s.add_dependency 'spicy-proton', '~> 2.1'
   s.add_dependency 'statsd-ruby', '~> 1.4'