Add Rack 3 and Rails 8.1 support

[nerisa]

Summary

This PR adds support for Rack 3.x and Rails 8.1+ to the sbmt-pact gem. The main issue is that Rack 3 removed Rack::Handler::WEBrick and moved it to the separate rackup gem.

Motivation

Rails 8.0+ requires Rack 3.x, and the current version of sbmt-pact only supports Rack 2.x. This prevents users from using the gem with modern Rails applications.

Changes Made

1. Updated sbmt-pact.gemspec

• Changed Rack dependency from ~> 2.0 to >= 2.0, < 4 (supports both Rack 2 and 3)
• Added rackup gem as a dependency

2. Updated lib/sbmt/pact/provider/http_server.rb

• Added require "rackup/handler/webrick"
• Changed Rack::Handler::WEBrick to Rackup::Handler::WEBrick

3. Updated lib/sbmt/pact/provider/pact_broker_proxy_runner.rb

• Added require "rackup/handler/webrick"
• Changed Rack::Handler::WEBrick to Rackup::Handler::WEBrick

Testing

All 60 existing tests pass successfully with these changes:

Finished in 0.21415 seconds (files took 4.15 seconds to load)
60 examples, 0 failures

The changes maintain backward compatibility with Rack 2.x while adding support for Rack 3.x.

Compatibility

• ✅ Backward compatible with Rack 2.x
• ✅ Forward compatible with Rack 3.x
• ✅ All existing functionality preserved
• ✅ No breaking changes

Additional Notes

These are the only breaking changes between Rack 2 and Rack 3 that affect this gem:

• Rack::Handler::WEBrick moved to Rackup::Handler::WEBrick
• Other Rack APIs (Rack::Request, Rack::CONTENT_LENGTH) remain unchanged
• The rack-proxy gem already supports Rack 3

This change enables users to use sbmt-pact with Rails 8.0+ applications.

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This PR was created with assistance from Claude Code