Add Rack 3.2 support

- Add gemfiles/rack_3_2.gemfile for testing with Rack ~> 3.2
- Update GitHub Actions workflow to include rack_3_2.gemfile in test matrix
- Ensures compatibility with latest Rack 3.2.x versions

Author: ericproulx

.github/workflows/test.yml

@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby: ['3.0', '3.1', '3.2', '3.3', '3.4']
-        gemfile: [Gemfile, gemfiles/rack_2_0.gemfile, gemfiles/rack_3_0.gemfile, gemfiles/rack_3_1.gemfile, gemfiles/rails_7_0.gemfile, gemfiles/rails_7_1.gemfile, gemfiles/rails_7_2.gemfile, gemfiles/rails_8_0.gemfile]
+        gemfile: [Gemfile, gemfiles/rack_2_0.gemfile, gemfiles/rack_3_0.gemfile, gemfiles/rack_3_1.gemfile, gemfiles/rack_3_2.gemfile, gemfiles/rails_7_0.gemfile, gemfiles/rails_7_1.gemfile, gemfiles/rails_7_2.gemfile, gemfiles/rails_8_0.gemfile]
         specs: ['spec --exclude-pattern=spec/integration/**/*_spec.rb']
         include:
           - ruby: '3.3'

CHANGELOG.md

@@ -18,6 +18,7 @@
 * [#2602](https://github.com/ruby-grape/grape/pull/2602): Remove `namespace_reverse_stackable` from public DSL interface and use direct inheritable_setting access - [@ericproulx](https://github.com/ericproulx).
 * [#2603](https://github.com/ruby-grape/grape/pull/2603): Remove `namespace_stackable_with_hash` from public interface and move to internal InheritableSetting - [@ericproulx](https://github.com/ericproulx).
 * [#2604](https://github.com/ruby-grape/grape/pull/2604): Enable branch coverage  - [@ericproulx](https://github.com/ericproulx).
+* [#2605](https://github.com/ruby-grape/grape/pull/2605): Add Rack 3.2 support with new gemfile and CI integration - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 #### Fixes

gemfiles/rack_3_2.gemfile

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+eval_gemfile '../Gemfile'
+
+gem 'rack', '~> 3.2'