Add dependabot instruction to ignore redis and sidekiq version upgrade

.github/dependabot.yml

@@ -5,6 +5,22 @@ updates:
     directory: /
     schedule:
       interval: monthly
+    ignore:
+          # TODO: Remove this ignore config once moved to a Redis v6.2+ instance in AKS.
+          # The version is currently pinned to <7. We're unable to upgrade sidekiq as it requires out Redis service
+          # instance to be 6.2+ https://github.com/sidekiq/sidekiq/blob/main/docs/7.0-Upgrade.md#version-support.
+          # Our current Redis service instance is 5.0.6. This will be upgraded when we migrate from GOVuk PaaS to AKS.
+          - dependency-name: "sidekiq"
+            update-types: ["version-update:semver-major"]
+
+          # TODO: Remove this ignore config once moved to a Redis v6.2+ instance in AKS.
+          # The version is currently pinned to <5 by sidekiq (version 6.5.8).
+          # It seems this pin is removed by later sidekiq versions, but we're unable to upgrade sidekiq as it requires out
+          # Redis service instance to be 6.2+ https://github.com/sidekiq/sidekiq/blob/main/docs/7.0-Upgrade.md#version-support.
+          # Our current Redis service instance is 5.0.6. This will be upgraded when we migrate from GOVuk PaaS to AKS.
+          - dependency-name: "redis"
+            update-types: ["version-update:semver-major"]
+
 
   - package-ecosystem: npm
     directory: /