Add support for ActiveRecord 8.0 and 8.1

[pjmartorell]

Summary

This PR adds support for ActiveRecord 8.0 and 8.1 to the migration-lock-timeout gem. Resolves #22

Changes

Gemspec

• Updated ActiveRecord dependency constraint from < 8.0 to < 8.2
• This allows support for ActiveRecord 8.0.x and 8.1.x releases

Test Configurations

Added 4 new Appraisal configurations:

• activerecord_8_0 - Testing with ActiveRecord 8.0.x
• activerecord_8_0_with_strong_migrations - Testing 8.0 with strong_migrations integration
• activerecord_8_1 - Testing with ActiveRecord 8.1.x
• activerecord_8_1_with_strong_migrations - Testing 8.1 with strong_migrations integration

Documentation

• Updated CHANGELOG.md to document new Rails 8.0 and 8.1 support

Testing

All tests pass successfully across all new configurations:

Configuration	ActiveRecord Version	Test Results
activerecord_8_0	8.0.3	✅ 13 examples, 0 failures
activerecord_8_0_with_strong_migrations	8.0.3	✅ 13 examples, 0 failures
activerecord_8_1	8.1.0	✅ 13 examples, 0 failures
activerecord_8_1_with_strong_migrations	8.1.0	✅ 13 examples, 0 failures

Compatibility Analysis

The gem's implementation uses only stable ActiveRecord APIs that have remained unchanged in Rails 8.x:

• ActiveRecord::Migration prepending and extending
• execute method for SQL commands
• disable_ddl_transaction attribute
• Migration direction checking (:up vs :down)

Rails 8.0 and 8.1 introduce no breaking changes to these migration APIs, ensuring full compatibility.

Version Support Matrix

With this change, the gem now supports:

• ✅ ActiveRecord 6.1.x
• ✅ ActiveRecord 7.0.x
• ✅ ActiveRecord 7.1.x
• ✅ ActiveRecord 8.0.x ⭐ NEW
• ✅ ActiveRecord 8.1.x ⭐ NEW