Update GitHub actions testing matrix

Author: tpritc

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
     name: 'Test Suite'
     strategy:
       matrix:
-        ruby: [2.7.6, 3.0.4, 3.1.2]
+        ruby: [3.2.8, 3.3.8, 3.4.4]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -26,11 +26,11 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7.0
+          ruby-version: 3.2.8
       - uses: actions/cache@v1
         with:
           path: vendor/bundle
-          key: bundle-2.7.0-${{ hashFiles('**/*.gemspec') }}
-          restore-keys: bundle-2.7.0
+          key: bundle-3.2.8-${{ hashFiles('**/*.gemspec') }}
+          restore-keys: bundle-3.2.8
       - run: bundle install --jobs 4 --retry 3 --path vendor/bundle
       - run: bundle exec rubocop