Use Ruby 3.4.

Author: dblock

.github/workflows/lint.yml

@@ -13,4 +13,5 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
+          ruby-version: '3.4'
       - run: bundle exec rubocop

.github/workflows/update.yml

@@ -15,6 +15,7 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
+          ruby-version: '3.4'
       - name: Download
         run: bundle exec rake api:download
       - name: Update

.github/workflows/validate.yml

@@ -12,5 +12,6 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
+          ruby-version: '3.4'
       - name: Validate
         run: bundle exec rake api:validate