CI: drop support for EOL Rubies (< 2.7), add support for Ruby 3.4, shift jRuby support from 9.2/9.3 -> 9.3/9.4

.github/workflows/ci.yml

@@ -2,34 +2,41 @@ name: CI
 on: [push, pull_request]
 jobs:
   test:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.flaky }}
+    name: "Tests: Ruby ${{ matrix.ruby-version }}"
+    if: "!contains(github.event.head_commit.message, '[skip ci]')"
     strategy:
       matrix:
-        ruby-version: ["2.5", "2.6", "2.7", "3.0", "3.1", "truffleruby-22", "truffleruby-21"]
+        ruby-version:
+          - 2.7
+          - "3.0"
+          - 3.1
+          - 3.2
+          - 3.3
+          - 3.4
+          - truffleruby-23
+          - truffleruby-24
         flaky: [false]
         include:
-          - ruby-version: "ruby-head"
+          - ruby-version: "head"
             flaky: true
-          - ruby-version: "jruby-9.2"
+          - ruby-version: "jruby-9.3" # Ruby 2.6.x support
             flaky: true
-          - ruby-version: "jruby-9.3"
+          - ruby-version: "jruby-9.4" # Ruby 3.1.x support
             flaky: true
           - ruby-version: "jruby-head"
             flaky: true
           - ruby-version: "truffleruby-head"
             flaky: true
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
 
       - name: Set up Ruby ${{ matrix.ruby-version }}
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
 
-      - name: Bundle install
-        run: |
-          gem install bundler
-          bundle install
       - name: Run Tests
         run: bundle exec rake test

.gitignore

@@ -4,3 +4,5 @@ coverage
 ri
 *.swp
 Gemfile.lock
+vendor
+.bundle