Redefine sidekiq requirement to not install beta version

Currently, bundler will install version `7.0.0.beta1` of sidekiq as it
considers this to be less than `7`. We do not want this to happen.

In #84, we changed the
requirement from `">= 6.5.12", "< 7"` to `"~> 6.5"`. This has a side
effect of some of our applications ending up on an earlier version of
sidekiq than `6.5.12` (there was a security fix in `6.5.10`).

Therefore in #85 we
changed the requirement to be `"> 6.5.10", "< 7"`, however this once
again resulted in bundler installing `7.0.0.beta`.

Updating the requirements again to be even more explicit, so we always
install a version newer than `6.5.12` but never a version that isn't
`6.5.x`.

CHANGELOG.md

@@ -1,3 +1,7 @@
+# Unreleased
+
+* Redefine sidekiq requirement so Bundler won't install 7.0.0.beta1
+
 # 7.1.4
 
 * Require sidekiq > 6.5.10 and < 7

govuk_sidekiq.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "gds-api-adapters", ">= 19.1.0"
   spec.add_dependency "govuk_app_config", ">= 1.1"
   spec.add_dependency "redis-namespace", "~> 1.6"
-  spec.add_dependency "sidekiq", "> 6.5.10", "< 7"
+  spec.add_dependency "sidekiq", "~> 6.5", ">= 6.5.12"
 
   spec.add_development_dependency "climate_control", "~> 1.2"
   spec.add_development_dependency "railties", "~> 7"