Add Ruby 3.3 and 3.4 to CI.

- add indirect dev dependency to gemsepc

Author: simi

.github/workflows/ruby.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         # Due to https://github.com/actions/runner/issues/849, we have to use quotes for '3.0'
-        ruby: [2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.2, truffleruby-head]
+        ruby: [2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.2, 3.3, 3.4, truffleruby-head]
 
     steps:
     - uses: actions/checkout@v2

knapsack.gemspec

@@ -30,4 +30,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'minitest', '>= 5.0.0'
   spec.add_development_dependency 'pry', '~> 0'
   spec.add_development_dependency 'timecop', '>= 0.9.4'
+
+  # needed for outdated spinach gherkin-ruby dependency
+  spec.add_development_dependency 'racc'
 end