Bump rails from 5.2.7.1 to 5.2.8.1

This release introduces an incompatibility in order to fix a security
issue when using YAML for serialization. We use YAML to serialize the
`ranges` column in the `legislation_annotations` table, so we have to
allow the `ActiveSupport::HashWithIndifferentAccess` class in order to
properly read this column.

Ideally we'd use a JSONB column for the ranges (like we do in other
places), but that would require migrating existing data.

Bumps [rails](https://github.com/rails/rails) from 5.2.7.1 to 5.2.8.1.
- [Release notes](https://github.com/rails/rails/releases)
- [Commits](https://github.com/rails/rails/compare/v5.2.7.1...v5.2.8.1)

---
updated-dependencies:
- dependency-name: rails
...

config/application.rb

@@ -21,6 +21,9 @@ module Consul
     # in any CONSUL installations
     config.active_support.use_authenticated_message_encryption = false
 
+    # Keep reading existing data in the legislation_annotations ranges column
+    config.active_record.yaml_column_permitted_classes = [ActiveSupport::HashWithIndifferentAccess]
+
     # Handle custom exceptions
     config.action_dispatch.rescue_responses["FeatureFlags::FeatureDisabled"] = :forbidden