Rails 8 Support

[matt423]

• Changes base fork which we've been using directly(which is why there's additional commits)
• Adds Rails 8 support

Copilot Summary

This pull request introduces several breaking and compatible changes to modernize the gem and remove legacy dependencies. The main focus is on dropping HAML support, updating Rails and Ruby compatibility, and simplifying the codebase and test matrix.

Compatibility and dependency updates:

• Added compatibility for Rails 7.1 and 8.0, and removed support for Rails versions below 6.1. Ruby support is updated to require Ruby >2.7 for newer Rails versions and >3.1 for Rails 8.0. [1] [2] [3] [4] [5] [6]
• The test matrix in .github/workflows/test.yml is simplified to only test supported Ruby/Rails combinations, removing all HAML-related gemfiles and legacy Rails versions. [1] [2]
• All HAML-related gemfiles and code have been removed, and the gemspec no longer requires HAML as a dependency. [1] [2] [3] [4] [5] [6] [7]

Codebase and documentation simplification:

• The README and gemspec have been updated to clarify the removal of HAML support and document new compatibility requirements. [1] [2] [3] [4]
• Refactored lib/angular_xss/erb.rb to use a simpler, modern approach for patching ERB escaping, and added escape_if_unsafe to centralize escaping logic. [1] [2]

Other improvements:

• Minor code cleanups and updates throughout, including removal of obsolete code and improved method organization. [1] [2] [3] [4] [5]

CHANGELOG and metadata updates:

• The CHANGELOG.md documents all breaking and compatible changes, including the removal of HAML support and new Rails compatibility.
• Updated gem metadata and file lists to match new code structure.

These changes modernize the gem, reduce maintenance overhead, and make it easier to use with recent Rails and Ruby versions.

---

Compatibility and dependency updates

• Added support for Rails 7.1 and 8.0; removed support for Rails < 6.1. Updated Ruby requirements for newer Rails versions. [1] [2] [3] [4] [5] [6]
• Simplified the test matrix to only test supported Ruby/Rails combinations and removed all HAML-related gemfiles. [1] [2]
• Removed all HAML-related gemfiles and code, including gemspec dependency. [1] [2] [3] [4] [5] [6] [7]

Codebase and documentation simplification

• Updated README and gemspec to clarify removal of HAML support and document new compatibility requirements. [1] [2] [3] [4]
• Refactored lib/angular_xss/erb.rb for modern Rails patching and centralized escaping logic. [1] [2]

Other improvements

• Minor code cleanup and improved method organization. [1] [2] [3] [4] [5]

CHANGELOG and metadata updates

• Updated CHANGELOG.md and gem metadata to reflect all breaking and compatible changes. [1] [2]